Class 7

SCERT AP 7th Class Maths Solutions Pdf Chapter 8 Exponents and Powers Ex 8.1 Textbook Exercise Questions and Answers.

AP State Syllabus 7th Class Maths Solutions 8th Lesson Exponents and Powers Ex 8.1

Questions 1.
Express the following into the exponential form:
(i) 14 × 14 × 14
Answer:
14 × 14 × 14 = 143

(ii) 25 × 25 × 25 × 25 × 25
Answer:
25 × 25 × 25 × 25 × 25 = 25

(iii) ab × ab × ab × ab
Answer:
ab × ab × ab × ab = (ab)⁴

(iv) 7 × p × p × q
Answer:
7 × p × p × q = 7 × p² × q

Question 2.
Express the following into expanded form:
(i) 27⁶
Answer:
27⁶ = 27 × 27 × 27 × 27 × 27 × 27

(ii) 101⁵
Answer:
1015 = 101 × 101 × 101 × 101 × 101

(iii) (2b)⁴
Answer:
2b⁴ = 2b × 2b × 2b × 2b

(iv) 3a⁸
Answer:
3a⁸ = 3 × a× a × a × a × a × a × a × a

Question 3.
Express the following In exponential form through prime factorisation: .
(i) 81
Answer:

81 = 3 × 27
= 3 × 3 × 9
= 3 × 3 × 3 × 3
∴ 81 = 3⁴

(ii) 125
Answer:

125 = 5 × 25
= 5 × 5 × 5
∴ 125 = 5³

(iii) 324
Answer:

324 = 2 × 162
= 2 × 2 × 81
= 2 × 2 × 3 × 11
= 2 × 2 × 3 × 3 × 9
= 2 × 2 × 3 × 3 × 3 × 3
∴ 324 = 2² × 3⁴

(iv) 1080
Answer:

1080 = 2 × 540
= 2 × 2 × 270
= 2 × 2 × 2 × 135
= 2 × 2 × 2 × 3 × 45
= 2 × 2 × 2 × 3 × 3 × 15
= 2 × 2 × 2 × 3 × 3 × 3 × 5
∴ 1080 = 2³ × 3¹ × 5¹

Question 4.
Compute and identify the greater num-ber in the following pairs : 7
(i) 2⁵ or 5²
Answer:
2⁵ = 2 × 2 × 2 × 2 × 2 = 32
5² = 5 × 5 = 25
32 > 25
Therefore, 2⁵ > 5²

(ii) 7³ or 3⁷
Answer:
7³ = 7 × 7 × 7 = 343
3⁷ = 3 × 3 × 3 × 3 × 3 × 3 × 3 = 2187
2187 > 343
Therefore, 3⁷ > 7³

(iii) 2³ or 3²
Answer:
2³ = 2 × 2 × 2 = 8
3² = 3 × 3 = 9
9 > 8
Therefore, 3² > 2³

Question 5.
Expand 3³ × 4² and 4³ × 3². Are they equal? Justify.
Answer:
3³ × 4² = 3 × 3 × 3 × 4 × 4
= 27 × 16 = 432

4³ × 3² = 4 × 4 × 4 × 3 × 3
= 64 × 9 = 576

432 × 576 (They are not equal)
Therefore, 576 > 432
So, 4³ × 3² > 3³ × 4²

Question 6.
Express the following numbers in exponential form with the given base.
(i) 1000, base 10
Answer:

∴ 1000 = 10 × 10 × 10 = 10³

(ii) 512 base 2
Answer:

512 = 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2
∴ 512 = 2⁹

(iii) 243 base 3
Answer:

243 = 3 × 3 × 3 × 3 × 3
∴ 243 = 3⁵

Question 7.
If a = 2, b = 3 find the value of
(i) a^a + b^b
Answer:
Given a = 2, b = 3
a^a + b^b = 2² + 3³
= (2 × 2) + (3 × 3 × 3)
= 4 + 27 = 31
Therefore, if a = 2, b = 3 then a^a + b^b = 31

(ii) a^b + b^a
Answer:
Given a = 2, b = 3
a^b + b^a = 2³ + 3²
= (2 × 2 × 2) + (3 × 3).
= 8 + 9 = 17
Therefore, if a = 2, b = 3
then a^b + b^a = 17

(iii) (a + b)^b
Answer:
Given a = 2, b = 3
(a + b)^b = (2 + 3)³ = 5³
= 5 × 5 × 5 = 125
Therefore, if a = 2, b == 3
then (a + b)^b =125

Question 8.
Write the following in Exponential form:
(i) The speed of light in vacuum is about 30,00,00,000 m/sec.
Answer:
Given the speed of light = 30,00,00,000 m/sec
= 3 × 10 × 10 × 10 × 10 × 10 × 10 × 10 × 10
∴ Speed of light = 3 × 10⁸ m/sec.

(ii) The population of India is about 121,00,00,000 as per 2011 census.
Answer:
Given population of India
= 121,00,00,000
= 121 × 10 × 10 × 10 × 10 × 10 × 10 × 10
= 11 × 11 × 10⁷
∴ Population of India = 11² × 10⁷ as per 2011 census.

AP State Syllabus AP Board 7th Class Science Important Questions Chapter 9 Reflection of Light

AP State Syllabus 7th Class Science Important Questions 9th Lesson Reflection of Light

7th Class Science 9th Lesson Reflection of Light Important Questions and Answers

Question 1.
When will you be able to see clear image of yourself in a plane mirror?
Answer:

1. Point a torch towards the mirror so that it’s light falls on the mirror which we hold up as shown in figure (a), and try to see our image in the mirror.
   
2. Now turn the torch towards our face as shown in figure (b), and see our image in the mirror.
   
3. We will find that when light is focused on our face we can see our image clearly in the mirror.
4. We also notice that when light is focused on the mirror we find a dim image of our face in the mirror.

Question 2.
Explain by a simple activity what are incident and reflected rays of light. What is reflection of light?
Answer:

1. Place a blank sheet of paper on the ground such that part of it is in the sunlight and other part of it is in the shadow.
2. Hold the mirror strip with the slit facing the sun.
3. Let a ray of light from the slit fall on the paper.
4. Now take another mirror strip and place it in the path of this light ray such that the ray coming from first mirror falls on the second mirror as shown in figure.
   
5. We did not see any other ray of light, apart from the one from the mirror slit, on the paper.
6. This effect of the mirror strip on the ray of light is called reflection.
7. The ray of light falling on the mirror is called the incident ray and the ray returning from it is called the reflected ray.

Question 3.
Explain the terms ‘Angle of incidence’, ‘Angle of reflection’ and ‘Normal at the point of incidence.’
Answer:

1. Take a sheet of blank paper. Draw a line segment AC across the middle.
2. Draw another straight fine at right angles (90 degrees) to segment AC.
3. The second line should bisect segment AC at point B. We shall call this line as Normal. See in figure, (a)
   
4. Draw two lines from point B on the left side of the normal and two on the right side. The lines should be at angles of 30° and 60° respectively from the normal. Number these lines 1, 2, 3, 4 as shown in figure, (b)
   
5. Place a mirror strip vertically on segment AC with its reflecting surface facing the normal.
6. See that the back of the mirror coincides with segment with a slit and let its light ray fall along line 4.
7. Now this ray is the incident ray for the mirror.
8. The angle between the normal and the incident ray is called the Angle of Incidence (∠i).
9. The angle between normal and the reflected ray (along line 1) is called the Angle of Reflection (∠r).
10. Adjust the mirror strip with the slit so that its light ray falls along line 3 and we find that the reflected ray falls along line 2.
11. Adjust the mirror strip with the slit so that its light ray falls along normal, then the angle of incidence is 0° (the angle between normal and incident ray “that is also normal here”, is 0°)
12. The reflected light reflects back along the normal itself.

Question 4.
What relationship exists between angle of incidence and angle of reflection? State it and prove the relation by a simple activity.
Answer:

1. In the case of reflection on mirrors the law of reflection is Angle of incidence ∠i = Angle of reflection ∠r.
2. Proof : by a simple activity.
   • Take a sheet of blank paper. Draw a line AC on it.
   • Draw another straight line at right angles to AC.
   • This line should bisect AC. This line is normal.
   • Draw two lines from point B on the left side of the normal and two lines on the right side of the normal.
   • The lines should make angles of 30° and 60° respectively from the normal. Number these lines as 1, 2, 3 and 4 as shown in figure.
     
   • Place the mirror strip vertically on AC. With its reflecting surface facing the normal.
   • Take the mirror strip with a slit and let its light ray fall along line 4.
   • We find the reflected ray coming along the line 1.
   • Note the angle of incidence and angle of reflection.
   • Repeat the experiment by sending the light ray along line 3.
   • The reflected ray is found to be along line 2.
   • Record the observations.
     
     It is clear from the above activity that angle of incidence ∠i = angle of reflection ∠r.

Question 5.
Describe a small activity to prove that it is possible to see the image of an object only when the incident ray, reflected ray and normal are at the same plane.
Answer:

1. Place a mirror (1ft. × 1ft.) on the floor. You and your friends A, B, C stand on four sides of the mirror as shown in figure.
2. Adjust your places of standing, in such a way that each one of you can see the image of the person opposite to you in the mirror kept on the floor.
3. Your friends A, C are able to see images of each other in the mirror.
4. Ask your friend – B, who is in front of you to move a feet aside from his place. You cannot see his image in the mirror.
   
5. Imagine a normal to the mirror. It would be perpendicular to the mirror as well as to the floor.
6. Imagine an incident ray coming from your friend B, falls on the mirror then the reflected ray from mirror reaches you.
7. Observe that the incident ray, reflected ray and normal lie in the same plane.
8. Now think why the image of your friend B is not visible to you when he moves aside. Where should.you stand to see his image? Once again imagine the incident, reflected rays and normal and assumed plane.
9. It is evident that the incident ray, reflected ray and normal should be in same plane, then only you can see your friend.

Question 6.
How would you get an image in a mirror?
Answer:

1. We see our image in a mirror many times. How it is formed?
2. During day time the light which falls on us gets reflected and a number of reflected light rays from us that fall on the mirror also get reflected back.
3. These reflected rays reach your eye and make us see our image.
4. See figure (a). Thus formation of image in mirrors is due to reflection of light rays from the mirror.
   
5. See the figure (b) and observe the lines. They will explain how the image of a candle is formed in the mirror and how we are able to see the image of the candle in the mirror.
   

Question 7.
What is the difference between you and your image in a mirror?
Answer:

1. Stand in front of a mirror as shown in figure (a) and observe on which side of you does the pocket on your shirt appear, when you look into the mirror.
   
2. Raise your right hand infront of a mirror as shown in figure (b). Which hand of your image appears raised?
3. To make your image to comb hair with its right hand, what will you have to do?
4. What do these observations suggest?
5. In a mirror, right of an object appears as left and left of the object appears as right.
6. Note that only sides are interchanged. This is called lateral inversion.

Question 8.
How can you make a garden in a box ? Describe the procedure.
Answer:

1. Take an empty shoe box. Place two plane mirrors along the edges.
2. See that the pair of mirrors are parallel to each other and their reflecting surfaces face each other as shown in figure.
   
3. Scratch the centre part of a mirror at its back and make a hole to the wall of the box such that it coincides with the scratched portion of the mirror.
4. Put some flowers in the box. Make a few holes in the lid before closing the box so that light enters into the box.
5. Now look through the hole. You can see a wonderful and beautiful vast garden.

Question 9.
Why does the small area look like a vast garden?
Answer:

1. The light which enters the box falls on the flowers, gets reflected and travels in all directions.
2. The rays which fall on the mirrors reflect back to the opposite mirror.
3. This process happens again and again.
4. Due to this multiple reflection we can see that small area as a big garden.

Question 10.
Explain what do you understand by regular reflection and irregular reflection.
Answer:

1. Reflection from a smooth surface like that of a mirror is called regular reflection (see figure a).
2. Clear images are formed in case of regular reflection.
3. Reflection from a rough or irregular surface is called irregular reflection or diffused reflection (see figure b).
4. Images are not clear in case of irregular reflection.
5. In some cases we can’t find the image at all.
   

Question 11.
Can we use rear view mirror in place of plain mirror? Yes /No give the reason.
Answer:
No. We cannot use rear view mirror in place of plane mirror. The reasons are:

1. In plane mirror we can see our images.
2. But in rear view mirror we cannot see our images. So there is no use to use rear view mirror.

Question 12.
A mirror is hanging in your room. Your friend is sitting in the same room in a chair. If your friend wants to see you in a mirror, how will you adjust your position? Explain. ’
Answer:
I will adjust my position according to the laws of reflection. According to the laws of reflection Angle of incidence = Angle of reflection. If my friend wants to see me in a mirror, I will adjust my position (i.e) the angle of incidence is equal to angle of reflection. Then my friend will see me in that mirror.

Question 13.
What are rays of light? How do you produce rays of light?
Answer:

1. Take a mirror strip and a black paper as shown in figure, (a)
2. Cover the mirror strip with black paper and cut a 1 mm wide slit in the black paper, as shown in figure b.
3. Hold the mirror strip with the slit facing the sun as shown in figure, (c).
   
4. We will see some light coming through the slit. Let this light fall on a sheet of paper spread on the ground.
5. Light coming from such a slit or any other small hole looks like a ray of light.

Question 14.
Why should we keep mirror strips parallel to each other in periscope? What happens if they are not parallel?
Answer:

1. In a periscope the incident ray for the second mirror is the reflected ray of the first mirror.
2. When these two mirrors are parallel to each other, only then the rays lie in the same plane and can pass through the windows of the periscope.
3. If these mirrors make some angle with each other, then the reflected ray of the first mirror may not reach the second mirror or the reflected ray of second mirror may not pass through the window of periscope.
4. In both cases we can’t see the object with the periscope.

Question 15.
Can you spell your name as it appears in a mirror? Spelling of my name is …………………..  It appears in the mirror as ……………
Answer:
The student has to do it.

Question 16.
Show that the size of an object and its image are same.
Answer:

1. Stand in front of a big mirror. Observe your image.
2. Step back two feet and step forward one foot. Observe your image while you move to and fro.
3. You notice that your image also move.
4. Estimate the distance from you to the mirror and the distance from the mirror to the image.
5. Is the size of your image equal to your size? Place an object in front of the mirror. Compare the size of the object with its image.
6. We notice that irrespective of the size of mirrors, the size of image and the size of object are equal.

Question 17.
How are multiple images of an object formed?
Answer:

1. Take two plain mirrors of same size and join them with a cellophane tape as shown in figure.
   
2. Fold the mirrors through certain angle and place an object between them. We see multiple images of the object.
3. Count the number of images after changing the angle between the mirrors.
4. If we change the angle between the mirrors the number of images of the object also changes.

Question 18.
Explain the formation of images with spherical mirrors.
Answer:

1. Place the concave and convex mirrors on two different V – stands.
2. Put two candles of same size in front of them as shown in figure.
   
3. Adjust the position of candles, to form clear images in the mirrors.
4. Observe the sizes of images.

Question 19.
What are real and virtual images? Explain with the help of an activity.
Answer:

1. Place a concave mirror on a V-stand.
2. Place a lighted candle in front of it. Place a thick white paper or white drawing sheet behind the candle.
3. This acts as a screen. See figure.
   
4. Adjust distances between candle and mirror, screen and mirror by moving them either forward or backward till a clear image appear on the screen.
5. Repeat the activity using a convex mirror and plane mirror in place of concave mirror.
6. The image that can be obtained on a screen is called a Real Image. We can see this image in the mirror too.
7. The image that can’t be obtained on a screen but can be seen only in the mirror is
   called a virtual image.

Question 20.
Explain how are we able to see the objects around us in day time?
Answer:

1. We already know that, to see any object, light should fall on it.
2. In daytime we are able to see all objects which are in our room even though sunlight does not fall directly on those objects.
3. The multiple reflection of sunlight from surfaces like wall, floor, ceiling etc, finally falls on the object and gets reflected by it and reaches us.
4. This enables us to see the object.

Question 21.
How do you make a periscope?
Answer:

1. We have to secure the following materials to make a periscope. Empty agarbatti box, two mirror strips, scale, pencil, blade, match box, candle, glue.
2. Close both ends of the agarbatti box. Draw squares at both ends.
3. Draw the diagonal to these squares as shown in figure.
4. Slit the diagonals with a blade. The slits should equal to the length of the mirror strips.
5. Fix the mirror strips in these slits as shown in figure (b). Take care to see that these mirror strips lie parallel to each other, with their reflecting surfaces facing each other.
   
6. Fix the mirror strips firmly to the box with a few drops of molten wax from a burning candle. We can also use glue or fevicol instead of wax.
7. Cut out two windows on the narrow sides of the box as shown in figure (c). The windows should open directly on the reflecting surfaces of the mirror strips.
8. Now the periscope is ready.

Question 22.
How would you use the periscope?
Answer:

1. When we look through window 2, We will be able to see things lying in front of window 1.
2. We hide behind a tree, we can easily see that is happening on the other side of the tree with this periscope.
   
3. Observe in figure the girl is viewing objects outside the room through the window while hiding herself in the room, with the help of a periscope.

Question 23.
Keep the mirrors in such a way that the angle between the mirrors is 90 degrees and observe the images and compare them with the object. What do you notice? Is there any difference between those images? Imagine the reason for that.
Answer:

1. We observe 5 images of the object .
2. The intensity of the images decreases.

Question 24.
What are spherical mirrors?
Answer:

1. We have seen the mirrors whose reflecting surfaces look like the head of a steel spoon.
2. The mirrors which contain curved reflecting surfaces are called spherical mirrors.

Question 25.
Why do we call concave and convex mirrors as spherical mirrors?
Answer:

1. Take a rubber ball and cut a portion of it with knife as shown in figure. Be careful. Ask your teacher to help you in cutting the ball).
   
2. The inner surface of the cut piece of ball is called concave surface and the outer surface of it is called convex surface.
3. If the reflecting surface of a mirror is concave, it is called a concave mirror see figure (a)
   
4. If the reflecting surface is convex, then it is called as convex mirror. See figure (b).
   
5. Any concave or convex mirror is a part of a sphere. Hence these mirrors are called spherical mirrors.

Question 26.
How is the image of a candle is seen in a mirror. Draw a diagram to explain.
Answer:

1. See the diagram below.
2. The ray of light from the candle is reflected at the mirror, and bounces off at the same angle as it come to the mirror.
   
3. Our eye does not know that the light has been reflected.
4. Our eye sees the object (the candle) in the mirror, and feels that light is coming from that candle which seems to be behind the mirror.
5. In this way we see an image of the candle.

Question 27.
Take a drawing sheet and cut it into a few pieces. Write an English letter in capitals on each piece of drawing sheet. Observe the images of the letters formed in the mirror as shown in figure.

1. Which of the images appear same as the original letter?
2. Which of them appear reversed? Why?

Repeat above activity with Telugu / Hindi / Urdu letters and also with numbers 1 to 9, then try to answer the above questions.
Answer:
This can be done by the student.

Question 28.
On the front side of ambulances, the word AMBULANCE is written like why?
Answer:

1. All vehicles should give way to an Ambulance.
2. When the driver has seen the vehicle behind it, letters written on it must be clearly visible.
3. So the letters Ambulance are written on the vehicle with lateral inversion.
4. When the image of these letters are seen in the rear mirror, they will be laterally inverted and the name Ambulance will be clearly visible to him.
5. The driver immediately gives way to that Ambulance.

Question 29.
Every day we see our image in a plane mirror. Is it a real or virtual image? How can you decide?
Answer:

1. It is a virtual image.
2. The image formed in a plane mirror cannot be caught on a screen.

Question 30.
Keep a mirror close to your face and look into it. Move the mirror backward and observe the image. What change do you observe? Try this activity using Convex, Concave mirrors. In which mirror do you get an inverted image ?At what distance does it happen?
Answer:

1. When the mirror moves by a distance of minimum 25 cm. then only we can see our image in the plane mirror.
2. If it is a concave mirror, as long as our face it with in the focus of the concave mirror a small virtual image of the face is seen.
3. When the concave mirror is at a distance beyond its focus, then the image formed will be bigger in size.
4. In the case of convex mirror a virtual, small image is formed in it when it is kept at a suitable distance form the face.

Question 31.
Why are rearview mirrors arranged for vehicles?
Answer:

1. The mirrors at both sides of driver in motor vehicles like bus, car, motor vehicles are rearview mirrors.
   
2. These are used by drivers to see vehicles which are moving behind or beside of the vehicle without turning
   their heads.

Question 32.
Take a plane mirror. Go to a vehicle. Observe your image in the rearview mirror and as well as in the plane mirror. What difference do you find?
Answer:
We have noticed that the image formed by the rearview mirror is smaller than the image in a plane mirror.

Question 33.
a) How is the image on the outer portion of the spoon?
b) How is the image on the inner portion of the spoon?
Answer:
a) The image on the outer portion of the spoon is small in size.

b) The image on the inner portion of the spoon is reversed.

Question 34.
Have you noticed the surface of reflection in a torch light or in a head light of a vehicle? What is its specialty?
Answer:

1. Observe the torch light or headlight of a vehicle.
2. We notice a concave mirror behind the bulb (see figure)
3. Due to this concave surface the brightness of a small bulb is increased.
   

Question 35.
What happens if the surface of reflection in the torch or in a head light of a vehicle is convex like in figure?

Answer:

1. The intensity of light totally decreases.
2. A convex mirror diverges the light rays.
3. So the rays of light from the bulb diverge out. Giving small intensity of light on the road.

Question 36.
How is concave mirror useful to dentists?
Answer:

1. Dentists use concave mirrors to examine our teeth (See figure).
   
2. These concave mirrors used by doctor help to see a bigger image of teeth.

Question 37.
In our daily life while we stand in front of windows we observe our images on the glass of some windows but don’t find images on the glass of some other windows. Why?
Answer:

1. Our image is clear when we stand in front of certain types of glass as shown in figure (a).
   
2. Our image is not clear when we stand in front of some other types of glass as shown in figure (b).
3. If the surface of the window glass is smooth, due to the regular reflection we are able to see our image in that glass.
4. But if the surface of the window glass is rough, due to the irregular reflection we can’t find our image or we find unclear images in that glass.

Question 38.
Observe the image of the sun or a tree in still water. Later, disturb the water by throwing a pebble. How does the image of the Sun or the tree appear now? Why?
Answer:

1. When the water is still, its surface will be smooth and regular reflection takes place on it.
2. The image of an object formed due to still water will be clear.
3. When water is disturbed, the surface of water becomes rough and irregular reflection takes palce.
4. Due to this irregular reflection the image of an object may not be formed, if formed it will not be clear.

Question 39.
How many images are formed if two mirrors are kept in 60° angle to each other?
Answer:
The angle between two plane mirrors = 60°
Number of images formed

5 images are formed.

Question 40.
Sasi asked her father to fix mirrors on her new house for elevation. But her father did not accepted. Imagine why he said like that.
Answer:

1. If we decorate the front portion of the house, accidents may happen.
2. Because sunlight falls on these mirrors and reflects back.
3. This reflected light may fall on the men and vehicles, leading to accidents.

Question 41.
You are given a mirror. How can you identify whether it is convex mirror or concave mirror?
Answer:
A)

1. If the reflecting surface of a mirror is concave, it is called a concave mirror.
2. These mirrors form real and inverted images.
3. These are used in headlights of vehicles. ENT doctors also use these mirrors for their observations.

B)

1. If the reflecting surface is convex, then it is called a convex mirror.
2. They always form erect and virtual images.
3. These are used in rear view mirrors of the vehicles.

Question 42.
The following experiment has been conducted in your laboratory.

Answer the following questions based on this.

1. Which mirror is used in this experiment?
2. How does the image of candle appear on the screen?
3. Since the image is caught on the screen, what is the name of the image?
4. What are the apparatus required to conduct this experiment?

Answer:

1. Concave mirror
2. Inverted
3. Real image
4. U-stand, mirrors, candle, matchbox, screen, scale.

Question 43.
List out the properties of a convex mirror.
Answer:
Properties of a convex mirror :

1. If the reflecting surface is convex, then it is called a convex mirror.
2. Always form erect and virtual images.
3. These are used in rear view mirrors of the vehicles.

AP State Syllabus AP Board 7th Class Science Important Questions Chapter 6 Weather and Climate

AP State Syllabus 7th Class Science Important Questions 6th Lesson Weather and Climate

7th Class Science 6th Lesson Temperature and Its Measurement Important Questions and Answers

Question 1.
How do elders predict rain?
Answer:

1. It is a common experience for everybody to hear elder people talking about the possible weather on a day before planning to celebrate a function of the family.
2. They do it by observation of different seasons.
   
3. Farmers listen to radio or watch T.V. for weather forecast.
4. They depend on these weather predictions to plan their agricultural activities.
5. These weather predictions effect our daily life.

Question 2.
How does the meteorological department make weather predictions?
Answer:

1. The meteorological department collects data and uses it to make predictions.
2. This is about weather of Hyderabad for three consecutive days.
   
3. We find that these aspects of weather keep changing.
4. The humidity, changes, the wind changes, the temperature changes the sunrise and sunset times change too.
5. Keeping all these things in consideration the department make weather predictions.

Question 3.
What aspects do you see in the weather record?
Answer:

1. We find that there are some changes in a day. But most of the day is normal.
2. The weather is a complex phenomenon that it can vary over very short periods of time.
3. Sometimes its sunny in the morning but clouds appear from somewhere and it starts raining.
4. Within a matter of a few minutes this gives way to bright sunshine.
5. We must have had several such experiences. The temperature, humidity, rain, wind speed change.
6. All this effects the life of human beings and other living organisms. This constitutes weather.

Question 4.
Describe the construction and working of six’s maximum and minimum thermometer.
Answer:
Description – and working:

1. Six invented the maximum minimum thermometer (MMT) thermometer to measure highest and lowest temperatures of’a place.
2. This consists of a cylindrical bulb A, connected through a U-shaped tube to spherical bulb B that contains alcohol.
   
3. When the temperature increases, the alcohol in the bulb A expands.
4. The mercury in the U tube goes up to the bulb B side and the indicatorfl^also moves up.
5. This indicates maximum temperature of the day.
6. If the temperature decreases,alcohol in the bulb A contracts then the mercury in the U-tube goes to the A bulb side and the indicator (I₂ ) also moves up.
7. This indicates the minimum temperature of the day.
8. After taking readings the indicators I₂ and I₁ are brought to their original places by using a magnet.

Question 5.
How do you find the magnitude of rain fall?
Answer:

1. Take a 10cm wide beaker and insert a funnel of the same width.
2. Keep the apparatus in an open place when it is raining.
   
3. The rain water would be collected through the funnel into the beaker.
4. After the rain is over, measure the amount of water collected in the beaker.
5. If the depth of water is 1 cm then that the magnitude of rainfall is 1 cm.

Question 6.
Observe the weather report (temperature and rain fall) of two places in our state. The average temperature and rain fall for the last 25 years of the particular month is given in the table.

Answer the following questions:
a) In which month was maximum temperatures recorded? Why?
Answer:
In the month of may maximum temperatures were recorded.
b) Comparatively which place is hot? Why?
Answer:
Rentachintala is comparatively hot because the average rainfall is less compared to Arogyavaram.
c) How can you say Arogyavaram is cooler than Rentachintala in summer?
Answer:

1. In Arogyavaram, in the mid summer, the maximum temperature recorded was only 33°C as against 41°C recorded in Rentachintala.
2. So Arogyavaram is cooler than Rentachintala.

Question 7.
What is meant by climate?
Answer:

1. The average weather pattern taken over a long time, say 25 years, is called climate of that place.
2. Broadly, the same patterns of temperature, rainfall, humidity wind speed that have been generally continuing for a long time, say the last 25 years, at a place gives the climate of that place.
3. If we find that temperature at a place is generally high for large part of the year, we say the climate of that place is hot.

Question 8.
How do we compare a place which is hot with a place which is cool?
Answer:
With the help of six’s maximum and minimum thermometer we compare a place which is hot with a place which is cool.

Question 9.
How do meteorologists measure the rain fall? What are its units?
Answer:
Meteorologists measure the rainfall using a ‘Rain gauge’. It is also called Udometer or Pulviometer or Ombrometer. They can measure exact amount of rainfall. Rainfall is expressed in centimeters or millimeters.

Question 10.
Why is it sweaty in Vijayawada and relatively less in Hyderabad in summer?
Answer:

1. Even though it is hotter, we do not sweat as much in Hyderabad.
2. In places near a river or in coastal regions the weather in summer is sweaty.
3. If we are in coastal region in summer we would feel very sweaty in addition to feeling hot winds.
4. That is why Vijaywada is more humid than Hyderabad.

Question 11.
Which region on the globe is very hot and which region is very cold?
Answer:
We know that in the equatorial region it is very hot and in the polar region, it is very cold.

Question 12.
Take a newspaper or watch the TV news and record the maximum and minimum temperature, rainfall, humidity and wind pattern of any 3 cities or towns in a table. Do this over a week.
Answer:

1. Here the maximum temperature recorded over a week in Hyderabad is taken.
2. We will plot the graph.
   
3. Graph showing the variation of maximum temperature during 10-14 Dec. 2011 at Hyderabad.

Question 13.
Collect weather reports of a nearby city from newspapers. Tabulate your Observations for a week and compare them.
Answer:

1. For guidance sample tabular form is given.
2. The student has to perform this activity.
   

Question 14.
Answer the following questions from the data collected.
a) When was the maximum temperature recorded?
b) When was the minimum temperature recorded? Why?
c) Is there any similarity in temperatures between your school and the nearest city?
Answer:
a) …………………………………..
b) …………………………………..
c) …………………………………..

Question 15.
a) Pravin has measured temperature of his village with the help of MMT (Maximum, Minimum thermometer.)
b) He expressed his observations through a graph.
c) The observations are also tabulated.
d) Look into them and answer the following questions.
a) For how many days did Pravin observe the temperature of his village?
b) On which day was the highest temperature recorded?
c) On which days did the lowest temperature fall?
d) Do you find any relation between 10th and 14th of December 2011? What is that?
e) Make a graph with your observations of maximum and minimum temperatures.

Answer:
a) For five days.
b) On 2nd, 3rd, 4th and 5th days the highest temperature was recorded.
c) On the 1st day the lowest temperature fall.
d) There is an increase in temperature and the rise in temperature was maintained for four days.
e) The student can do this activity.

Question 16.
How do you find the direction of the wind? Describe an activity.
Answer:

1. Let us find the direction of wind by using card board pieces and a thin nail.
2. Take two cardboard pieces and cut them the shape of an arrow and paste them together.
   
3. Insert a thin needle or iron wire as shown the figure in the middle of the arrow.
4. The needle must be long enough to be fixed on a strong base and should allow the arrow to move along the direction of the wind.

Question 17.
With the help of an anemometer observe the directions of the wind and tabulate your observations in the table given here.

Now answer the following questions:
a) Does the wind move in the same direction the whole day?
Answer:
The student can answer this by observing the data collected by him / her.
b) In which direction does it move in the morning?
Answer:
This question also can be answered by the student.

Question 18.
What is humidity? Explain it with an activity.
Answer:
Humidity: The quantity of moisture in the air is the ’humidity’ of the place. If the humidity is high when it is hot, we feel sweaty.
Activity:

1. Take about 10 ml. of water in a test tube. Heat it on a Bunsen burner or a candle.
2. When water is heated, it changes into water vapour. The vapour enters into the air.
3. In the same way sea water changes into vapour due to heating by the sun.
4. That water vapour in the atmosphere is the humidity.

Question 19.
What happend during the tsunami in Andaman and Nicobar islands in 2004?
Answer:

1. Many people died during the tsunami in Andaman and Nicobar islands in 2004.
2. But the tribals who observed the ocean moving back and birds making sounds moved away from danger.
3. They could predict the danger and save their lives.

Question 20.
Write a weather report similar to the weather report given in Television.
Answer:

1. Isolated rain or thunder showers are lightly to occur over Chittoor, Nellore, Prakasham and some parts of Kadapa districts.
2. Mainly dry weather will prevail over southern Telangana districts and northern coastal districts of Andhra Pradesh.
3. Sky should be cloudy for the next two days in Kurnool and Ananthapur districts.

Question 20.
Describe a weather report actually given by the department.
Answer:

1. According to meteorological department report 42°C maximum temperature recorded at Ramagundam of Karimnagar district and 29°C minimum temperature recorded at Aarogyavaram of Chittore district.
2. Because of cumulonimbus clouds 2mm of rainfall was recorded in Hyderabad.
3. Scattered rainfall recorded in some parts of interior Rayalaseema.
4. Remaining part of the state was dry.

Question 21.
What is the difference between a weather forecast and a weather report?
Answer:

1. The report that explains future conditions is a weather forecast.
2. The report that explains about past conditions is a weather report.
3. In common conversation we often refer to both as weather report.

Question 22.
What are the weather components?
Answer:
Temperature, rain fall, wind speed, humidity…. etc., are the weather components.

Question 23.
How do farmers estimate the rain fall?
Answer:

1. Farmers estimate the rainfall based on the wetness of the soil after the rain.
2. They call-it as “PADUNU”.
3. This much of rainfall is sufficient to start agriculture activities like ploughing.
4. This is an approximate measure.

Question 24.
Draw the diagram of an Anemometer what is its use?
Answer:
We can measure wind speed and direction with an Anemometer.

Question 25.
Observe features of the following states, and specific places in India from an ATLAS. Try to write down something about the climate in these areas.

Answer:
The student with the help of the teacher can write something about the climate in those areas.

Question 26.
Describe the climate of our country as per the studies of IMD.
Answer:

1. The Indian Meteorological Department (IMD) studies climate of our country.
2. Climate describes the weather condition occurring over a relatively longer period of time in a given place.
3. For example in the month of June.
4. We expect the weather to be mild in Bangalore, humid in Kolkata, hot and dry in parts of Rajasthan, cold in Kashmir and rainy in Coastal Kerala.
5. Does it mean that in coastal Kerala it is always rainy in the month of June or if it would be always humid in Kolkata?
6. Nowadays there is a complaint that climate is not as ordered as it was .
7. Seasonal climatic condition do not appear as predictable and known.

Question 27.
How do people adjust to the climate? Why in 2010 Kurnool and other parts in Rayalaseema submerged infloods?
Answer:

1. The people living in an area adjust to the conditions of climate.
2. For example the rain fall has being relatively less for the past two decades.
3. Even in Rayalaseema during rainy season the tanks and canals remain dry.
4. The dried canals and tanks are now used for other purposes.
5. The less rainfall has also led to developing ways to use less water.
6. The change in rainfall pattern shows there may be shifts in climate over long periods of time.
7. In areas which do not have a climate of rain when it rains heavily there is no way to drain out the water.
8. As a result many areas were flooded and submerged in Kurnool in 2010 and also in other parts of Rayalaseema.

Question 28.
How does climate effect our life style?
Answer:

1. Climate mostly effects on our daily life. We change our life style to suit that climate.
2. We wear cotton clothes in summer.
3. We want to drink cool water also.
4. We take care to protect ourselves from rain.
5. We take many precautions we need to take if we were going to visit Kashmir or Ooty during winter.

Question 29.
a) The students of Sanjamala village collected the information about the temperature of their village in 5 days and reported in the table. Observe the table.

Answer the following questions:
i) On which day was Maximum Temperature recorded?
ii) On which day was Minimum Temperatrue recorded?
iii) What is the average Minimum Temperature of 5 days?
iv) What changes did you observe in the Temperature?
b) Draw a graph based on the information in the table.
Answer:
a) i) 02-01-2018
ii) 05-01-2018
iii) 19°C
iv) Lowest and highest temperatures.
b)

Question 30.
What aspects should you observe to predict the weather of your village, by watching sky?
Answer:
The time of sunrise and sunset, wind flow, percentage rainfall in that area should be taken into consideration to estimate the type of weather in that given area.

Question 31.
Table showing the variation of maximum and minimum temperature during the period between 10 and 14 September 2017 at Guntur. Based on this draw a graph.
Answer:

Question 32.
Observe the table and write answers for the following questions.

i) This table indicates ………….
ii) In which month was maximum rainfall recorded?
iii) Least temperature was recorded in which month?
iv) Why is maximum temperature recorded in the month of May?
Answer:
i) The above table tells us about the temperature and rainfall from May to November.
ii) November.
iii) November.
iv) Because May falls in summer.

Question 33.
Observe the below table and write answers for the following questions.

i) What aspects did you see in the weather record?
ii) Rainfall was recorded on which day?
iii) On which day was maximum temperature recorded?
iv) Among these three days, long day is observed on?
Answer:
i) Maximum temperature, minimum temperature, rainfall, sky, air, humidity, sunrise, and sunset.
ii) Second day
iii) Third day
iv) First day

Question 34.
Observe the diagram and answer the following questions.

i) What is the name of the apparatus in the picture?
ii) Name the liquid present in bulb – A.
iii) Name the liquid present in U-shaped tube.
iv) How is it useful in daily life?
Answer:
i) Six’s maximum minimum thermometer
ii) Alcohol
iii) Mercury
iv) To measure the maximum and minimum temperature of a day.

Question 35.
Observe the graph showing rainfall of a place from August to December. Write down the observations from it and answer the following questions.

i) Name the month in which minimum rainfall was recorded.
ii) Name the month in which maximum rainfall was recorded.
iii) Name the months in which less than 50 mm rainfall I was recorded.
iv) In which months was the rainfall recorded more than 50 nun?
Answer:
i) September.
ii) November.
iii) August, September and October.
iv) November and December.

Question 36.
Ritwik observed the temperature of his village and drew the following graph Analyse the graph and answer the following questions.

a) How many days does Ritwik observe temperature?
b) On which day the lowest temperature is recorded?
c) In which days does the temperature remain same?
d) What apparatus is used to measure the temperature?
Answer:
a) 5 days.
b) First day
c) 2nd, 3rd, 4th and 5th days.
d) Six’s maximum-minimum thermometer.

AP State Syllabus AP Board 7th Class Science Important Questions Chapter 8 Air, Winds and Cyclones

AP State Syllabus 7th Class Science Important Questions 8th Lesson Air, Winds and Cyclones

7th Class Science 8th Lesson Air, Winds and Cyclones Important Questions and Answers

Question 1.
How do you prove that air exerts pressure?
Answer:

1. We know that a bicycle tube or tube of any other vehicle can burst when it is over filled with air.
2. Take a balloon and fill it with air. Keep blowing more and more air into it.
3. The balloon expands and after a point bursts.
4. The reason for the burst is the increase in air pressure inside them.
5. For example a balloon being filled with air, the air filled football that becomes hard, water rising through a hand pump, the tubes of cycle, scooter or car are all due to the pressure exerted by air.

Question 2.
How do you show that air exerts pressure by a simple experiment?
Answer:

1. Take a syringe and draw out its plunger (piston) to the limit.
   
2. Close the nozzle of the syringe with a finger and press the piston.
3. The finger experiences the pressure exerted by air.

Question 3.
What happens on heating air? How is pressure related to this?
Answer:

1. It is important to remember that on heating the air expands and occupies more space.
2. When something occupies more space, it becomes less dense.
3. The warm air is therefore less dense than cold air. Thus smoke and hot air go up.
4. Similar to observations of activities done so far, numerous factors contribute to heat air.
5. When the air rises up, air pressure at the place becomes low and we have many kinds of winds as air comes into occupying areas of lower pressure.
6. The differential heating of land and water by the sun leads to land and sea breeze.

Question 4.
How are land breeze and sea breeze developed?
Answer:

1. The land heats up faster than the sea, so warm air rises over the land during the day as it is warmed by the Sun.
2. At certain times of a year, this can create a sea breeze which is a gentle breeze blowing into the land.
   
3. At night, the land cools faster than the sea, reversing the air flow.
4. This creates a land breeze that blows out to sea.

Question 5.
How are we getting monsoon winds? In which months do they come?
Answer:

1. We have read about the sea breeze and the land breezes.
2. In summer, near the equator the land heats up faster and during the day the temperature of the land is higher than the water in the ocean.
3. The air over the land gets heated and rises.
4. This causes the winds to flow from the oceans towards the land.
5. These are monsoon winds.
6. This is usual during the months of June to September.

Question 6.
How are winds useful in our life?
Answer:

1. The direction of the wind flow gets usually reversed in the months from December to early March.
2. The wind flows from the land to ocean as the sea cools more slowly.
3. The winds from the oceans carry water and bring rains.
4. Farmers in our country depend mainly on rains for their harvests.
5. We can also generate energy from high-speed wind.
6. Thus we can see the usefulness of winds in our life.

Question 7.
Describe how cyclones are formed.
Answer:

1. Tropical cyclones are like giant engines that use warm moist air as fuel.
2. The warm moist air rises upward from near the surface.
3. The warm air rises causing an area of lower air pressure below.
   
4. Air from surrounding areas of high air pressure pushes into the low pressure area.
5. Then this “new” air becomes warm and rises too.
6. As the warm air continues to rise, the surrounding air swirls – into take its place and the water from the sea surface also comes up with the air.
7. As the warmed moist air rises and cools off, the water in the air forms clouds.
8. The whole system of clouds and winds spins and grows, fed by the ocean’s heat and water evaporating from the surface. See the figure.
9. These kinds of satellite images help us to predict the path of the cyclones to some extent.

Question 8.
Write the Do’s and Don ‘ts during cyclones.
Answer:
Cyclones – Do’s and Don’ts:

1. We should not ignore the warnings issued by the meteorological department through T.V., Radio or newspapers: Pass on the information to others and ignore rumors.
2. When a cyclone alert is on for your area, continue normal working but stay alert to the radio warnings.
3. We should make necessary arrangements to shift essential household goods, domestic animals and vehicles, etc. to safer places.
4. Switch off electrical mains in your house.
5. Keep ready the phone numbers of all emergency services like police, fire brigade, and medical centres.
6. Pack essentials for yourself and your family to last few days, including medicines, special food for those who would need it. This may include babies and elders.

Question 9.
Write the precautions to be taken before the cyclone.
Answer:
Precautions to be taken before a cyclone:

1. We should be cautious about rumours.
2. If we feel that houses are not safe at the time of cyclone, we have move into a pucca building in the vicinity.
3. We should keep mobile phones in a waterproof bag, fully charged. If we have more than one mobile phone, we have to use one phone at a time, leaving the other phones switched off and using them one after the other to ensure communication to the longest possible period.
4. If we have to vacate the house close the toilet seat with sandbags.
5. We should close the drainage holes to prevent reverse flow of sewage.
6. The trained students should cooperate with the response teams.
7. We should make necessary arrangements to shift essential household goods, domestic animals and vehicles, etc. to safer places.

Question 10.
What are the post-cyclone measures?
Answer:
Post cyclone measures :
If you are staying in a cyclone hit area-

1. Strictly avoid any loose and dangling wires.
2. Do not drink water that could be contaminated. Always store drinking water for emergencies.
3. Whenever there is an outbreak of dysentery, we should take tea, decoction and starch solution (Ganji).
4. We should not go near to bunds of tanks, streams, the river banks, fallen trees, buildings, poles and seashores to play or sight-seeing and taking selfies.
5. Cooperate and help your neighbours and friends. First aid should be provided to the injured.
6. At the time of cyclones, some people lose their beloved family members and children or pets. In such situations, we should give assurance, guidance and counselling in order not to go to a depressed state.

Question 11.
Establish the fact that moving air creates low pressure.
Answer:

1. Take a glass and a postcard.
2. Keep the glass on a table and the postcard on the glass.
   
3. Wave our hand or note book above the postcard to displace the air just above the postcard.
4. As the card moves, it moves the air there creating low pressure.
5. Due to this low pressure the card on the glass rises up.
6. It means moving air creates low pressure.

Question 12.
What are the reasons that different areas have different temperatures? How does this help in getting rain?
Answer:

1. Uneven heating takes place on the surface of the earth.
2. We know that regions close to the equator gets more heat from the sun.
3. This is because of the direction of the sunlight being straighter close to the equator.
4. The air in these regions gets warmer.
5. The warm air rises, and the cooler air from the regions in the 0 – 30° latitude belt on either side of the equator moves in.
6. This movement of air sets forth winds that move over the earth.
7. We have also seen that the increased wind speed is accompanied by a reduced air pressure and this aids rains.

Question 13.
Do winds cause harm? Explain.
Answer:

1. We are familiar with the word cyclone.
2. During the months of May – June or October – November reports about them can be seen in the Newspapers and TV.
3. This way winds cause harm.

Question 14.
Where do we And air? Explain it with an activity.
Answer:

1. Take a bucket full of water and transparent glass.
2. Take a paper, crumple it into a ball and push it to the bottom of the glass.
3. Invert this glass and immerse it into the bucket of water. Keep the glass straight and press it so that the glass is completely under water.
   
4. Take it out and observe what happens.
5. The paper in the glass did not wet.
6. However if the glass is tilted air in the glass escapes as bubbles through water and water enters the glass.

Question 15.
Describe a simple activity to show the presence of air.
Answer:

1. Fill a bucket with water.
2. Take a bottle with a narrow mouth and immerse it in the bucket till it fills with water.
   
3. During the time the bottle is filling with water bubbles of air come out of the glass.
4. This air is earlier filled in the glass. So the glass is not empty but full of air.
5. Any bottle, glass or any other container that appears empty is actually full of air.
6. Nothing can be added to it unless the air inside is removed.
7. It is only when some air is removed that something else can enter.
8. Air occupies the space around us.

Question 16.
Show by a simple experiment that air expands on heating.
Answer:

1. Take an empty injection bottle and one empty ball point refill.
2. Remove the pin of the refill and insert one of its ends in the cork of the injection bottle as shown in Fig.
3. Put a water drop on the upper end of the refill.
   
4. Rub your hands together so that they become warm.
5. Carefully pick up the bottle and hold it in both your hands for sometime.
6. So that the bottle also becomes warm.
7. The water drop inflate in the refill.
8. This is because air in the bottle expands due to the heat supplied by the hands.

Question 17.
‘Hot air is lighter than cold air’. How do you prove it?
Answer:

1. Take two paper bags or empty paper cups of the same size.
2. Take a broomstick. Hang the two bags in the inverted position on the two ends of the broomstick.
3. Tie a piece of thread in the middle of the stick. Hold the stick by the thread, like a weighing balance.
   
4. Put a burning candle below one of the bags as shown in the figure (b) and observe what happens.
5. Note that we have used paper bags or cups as they are of a light weight and it would be easier to see the results of this experiment if we take any such light objects to hang on the thread.
6. The balance of the bags is disturbed.
7. This proves that hot air is lighter than cold air.

Question 18.
‘Air moves from a region of higher pressure to a lower pressure’. Prove this statement by a simple experiment.
Answer:

1. Take a balloon. Blow air into it. As we fill it up, it expands and it becomes harder to press the walls of the balloon. The inside air exerts pressure on the walls of the balloon.
2. Open the mouth of the balloon slightly. Air from the balloon comes out.
3. We can open the mouth less or more and control the flow of air.
4. The air in the balloon is at high pressure and it goes towards low pressure area.
5. We already know that when air moves, it is called wind. Air moves from the region where the air pressure is high to the region where the pressure is low.

Question 19.
How can you demonstrate that warm air rises up?
Answer:

1. Take an incense stick (agarbati) and light it. Observe the smoke of the incense stick.
2. When something occupies more space, it becomes less dense. The warm air is therefore less dense than cold air.
3. The smoke rises up indicating that warm air rises up.

Question 20.
Write an activity to prove that moving air creates low pressure.
Answer:

1. Wet the edges of glass and put a postcard on it, and hold it inverted with our left hand as shown in figure and move your right hand or note book to move the air form under the paper.
   
2. Due to the movement of the hand or note book, air there moves fast.
3. This moving air creates low pressure and the postcard is pushed out by the air inside the glass.

Question 21.
Prove by an activity that increased wind speed is accompanied by a reduced pressure.
Answer:

1. Take a glass containing water and two straws. Keep one straw in the water and another in horizontal direction as shown in figure and blow through the horizontal straw.
   
2. When you blow over the straw the water comes out due to low pressure which forms inside the straw.
3. So the water from the glass reaches up in the straw due to high pressure.
4. We see that the increased wind speed is accompanied by a reduced air pressure.

Question 22.
What is a cyclone? What are the other names for it?
Answer:

1. Cyclones are a form of violent storms on earth.
2. People call these storms by names such as typhoons, hurricanes, etc. depending on where they occur.

Question 23.
What factors contribute to cyclone? When and where do they likely to occur?
Answer:

1. Factors like wind speed, wind direction, temperature and humidity contribute to the development of cyclones.
2. In India cyclones usually occur in the month of May – June and October – November.
3. More cyclones tend to occur on the eastern side i.e. towards Bay of Bengal.

Question 24.
What are the effects of cyclone? On what factors the destruction of a cyclone depends?
Answer:

1. Cyclones can be very destructive.
2. The main effects of cyclones include heavy rain and strong wind.
   
3. The destruction of a cyclone depends mainly on its intensity, its size and its location.

Question 25.
What are the steps needed to use a dropper? Explain its functioning.

Answer:
Fig. (a): The air present in the tube of the dropper is removed by pressing the rubber head.
Fig. (b): Putting the open end of the tube of the dropper in water and releasing the pressed rubber head.
Due to low pressure in the tube water enters into it.
Fig. (c): Rubber head is made free from pressing. Water entered in to the tube of the dropper as air there was already sent out.

Question 26.
What is wind?
Answer:

1. The air around us is rarely still. It moves continuously from one direction to another.
2. The movement is in many directions.
3. This is what we call winds.
4. So we know that wind is moving air.

Question 27.
What are the advantages of advanced technology with regard to cyclones? How do you appreciate it?
Answer:

1. Advanced Technology has helped and these days we are better protected.
2. In the early part of last century, coastal residents may have had less than a day to prepare or evacuate their homes from an oncoming cyclone.
3. The world today is very different.
4. Thanks to satellites and radars, a cyclone alert or cyclone watch is issued 48 hours in advance of any expected storm and a cyclone warning is issued 24 hours in advance.
5. The message is broadcast every hour or half an hour when a cyclone is near the coast.
6. Information about cyclones will be given by the Indian Meteorological Department (IMD).

Question 28.
What are the post cyclone measures we have to take?
Answer:
Post cyclone measures: If you are staying in a cyclone hit area

• Strictly avoid any loose and dangling wires.
• Do not drink water that could be contaminated. Always store drinking water for emergencies.
• Do not go out for the sake of fun.
• Cooperate and help your neighbors and friends.

Question 29.
Observe the experiment and answer the following questions.

1. What happens to the water drop in the refill?
2. Why is the position of water drop changed?

Answer:

1. The water drop inflates in the refill.
2. Because we know that air expands on heating. So. the water drop is moved upwards. Hence, there is a change in the position of the water drop.

Question 30.
Observe the experiment and answer the following question. When two identical, inverted paper bags are hung on a balance, they balance each other as shown in right figure.

i) After a burning candle is placed under one of the bags as shown in the left figure, why is the balance of the bags disturbed?
Answer:
As the air beneath the cup heats up and moves, the cup of the balance raises up.

Question 31.
What measures will you take to protect your village from an approaching cyclone?
Answer:
I would follow the below methods to protect my village during cyclone.

1. I would convey the information of cyclone throughout the village.
2. I would store all the food grains, medicines, first aid things sufficient for a few days.
3. I would help people to move to a safe place.
4. I would make sure to keep a radio and batteries along with me.
5. I would keep necessary phone numbers of fire, police, etc. to get emergency services.
6. I would help people whenever they are in danger.

AP State Syllabus AP Board 7th Class Science Important Questions Chapter 5 Temperature and Its Measurement

AP State Syllabus 7th Class Science Important Questions 5th Lesson Temperature and Its Measurement

7th Class Science 5th Lesson Temperature and Its Measurement Important Questions and Answers

Question 1.
What are the different clothes we wear in different seasons?
Answer:

1. We wear woolen and dark coloured clothes during winter when it is cold outside.
2. Woolen and dark coloured clothes keep us warm.
   
3. We prefer to wear light coloured cotton clothes when it is hot.
4. They give us a feeling of coolness.
5. It is a wonder why a particular type of cloth is suitable for a particular season.

Question 2.
When rice is being cooked you observe the plate on the rice bowl jumps! Why is it happening?
Answer:
The heat energy converts water into steam and the pressure of steam throws away the lid.

Question 3.
Have you observed water boiling in a vessel with a lid on it? What do you notice? How can you establish that heat is a form of energy?
Answer:

1. We know that boiled water is being converted to water vapour.
2. The volume of the water vapour increases.
3. The increased volume of vapour tries to go out. In this process it tries to lift the lid up.
4. We need energy to lift any object. This energy comes from the heated water.
5. Water gets the energy from the heat of the fire. Thus heat is a form of energy:

Question 4.
What is heat?
Answer:

1. We feel hot when we sit in sunlight or near fire. We feel cold when we put a piece of ice on our palm.
2. We know that heat is a form of energy that is transferred from an object at higher temperature to one at lower temperature.
   
3. When we stand in the sun or near fire, heat energy enters our body and we feel hot. When ice is put on our palm, heat energy moves from our body to the piece of ice.
4. That’s why we feel cold.
5. “The energy which makes an object appear hot or cold is called heat.”.

Question 5.
What happens in the following?
a) Rub your palms together. How do you feel?
b) Have you ever observed that iron becomes hot when it is beaten with a hammer?
c) Take a soapnut seed. Rub it on a stone and touch it. How do you feel?
Answer:
In above cases mechanical energy is converted into heat energy.

Question 6.
Explain the terms ‘heat’ and ‘temperature’.
Answer:

1. If we stand close to fire, we feel warm.
2. When a warm object is placed close to a cooler object, heat energy moves from the warmer object to the cooler one until both objects attain the same temperature.
3. Often we think that heat and temperature are the same things. This is wrong.
4. Temperature is a measure of the heat energy in a body which indicates the ability of a body to give heat to another body or absorb heat from another body.
5. We use thermometers to measure temperature.

Question 7.
What are the properties of mercury?
Answer:
Properties of Mercury:

1. Its expansion is uniform. (For equal amounts of heat it expands by equal lengths.)
2. It is opaque and shining.
3. It does not stick to the sides of the glass tube.
4. It is a good conductor of heat.
5. It is easily available in pure state.

Question 8.
Write the properties of alcohol.
Answer:
Properties of Alcohol:

1. It can record very low temperatures.
2. Its expansion per degree Celsius rise in temperature is very large.
3. It can be coloured brightly and hence is easily visible.

Question 9.
Who first designed the thermometer? What do you know about it?
Answer:

1. First thermometer was invented by Galileo in 1593 AD.
   
2. In this thermometer air was used as the thermometric substance as air rapidly expands on heating and contracts on cooling.
3. Further, the substance that is used in the thermometer has uniform expansion or contraction with the rise or fall in temperature.

Question 10.
Do you find any difference in temperature of air in shadow and in the sun?

Measure temperature of air using a thermometer. What will you do to keep a thermometer in close contact with air?
Answer:

1. The temperature of air will be more as it receives heat directly from the sun and from reflected radiations.
2. The temperature in the shadow will be relatively less as only reflected radiant heat reaches there.

Question 11.
Is there any difference in temperature with variation of time or place?
Answer:
There is difference in temperature with variation of time or place.

Question 12.
Why do you use an umbrella in the hot sun during summer?
Answer:
To avoid direct heat radiations from the sun.

Question 13.
Write a note on the variations of temperature on different occasions and at different places over the globe?
Answer:

1. In Lybia (Africa) on a particular day in the year 1922, it became so hot that the temperature of air even in shade was as high as 58 °C.
2. At some places (Rentachintala of Guntur District) in Andhra Pradesh, the maximum temperature of air sometimes reaches 48 °C and more.
3. When it is so hot we feel extremely uncomfortable as the normal temperature of the human body is 37 °C.
4. The lowest temperature in the world has been measured in Antarctica where it once went down to about -89 °C.
5. The minus sign is used for temperature which is less than 0 °C. Water freezes at 0 °C, just think how cold -89 °C must be.
6. In winter when the atmospheric temperature around us becomes 15 °C – 20 °C we begin to feel cold.

Question 14.
What is a clinical thermometer ? Describe its construction.
Answer:

1. Thermometer which is used to find out the temperature of our bodies is called Clinical Thermometer.
   If we observe Thermometer carefully. There are two types of scales marked on the clinical thermometer one that starts with 35 degrees and ends at 45 degrees is Celsius scale. While the other that starts with 95 degrees and ends at 110 degrees is the Fahrenheit scale.
2. We see a kink in the capillary near the bulb.
   
3. This kink prevents Mercury level from falling on its own.

Question 15.
What is the value of one division on the fahrenheit scale on thermometer?
Answer:

1. Note the temperature difference indicated between the two bigger marks.
2. Also note down the number of divisions between these marks.
   
3. Suppose two consecutive bigger marks differ by one degree and there are five divisions between them.
4. Then one small division reads
   1/5 = 0.2 °F

Question 16.
Describe how do we use a clinical thermometer.
Answer:

1. We should wash the thermometer preferably with an antiseptic solution.
2. Holding it firmly by the end and give it a few jerks. These jerks will bring the level of mercury down. Ensure that it falls below 35 °C (95 °F).
3. Now we should plape the thermometer under our tongue or arm pit.
4. After one minute, we have to take the thermometer out and note the reading. It tells our body temperature.

Question 17.
How can you decide whether one has fever or not?
Answer:
The normal temperature of human body is 37°C (98.6°F). If one has body more than 98.6°F can consider as fever.

Question 18.
Write a note on a) Thermister thermometer and b) Digital thermometer.
Answer:
a) Thermister thermometer:
It is available in market to measure the human body tempera¬tures, particularly for infants and children.

b) Digital thermometer:

1. There is a lot.of concern over the use of Mercury in thermometer.
   
2. Mercury is a toxic substance and is very difficult to dispose of if a thermometer breaks.
3. These days digital thermometers are also available which do not use Mercury.

Question 19.
What precautions are suggested in using a clinical thermometer?
Answer:

1. We are advised not to use a clinical thermometer for measuring the temperature of any object other than human body.
   
2. Also we are advised to avoid keeping it in the sun or near a flame.

Question 20.
Measure the temperature of a person with clinical and digital thermometers.
Are the temperature readings same or different? Explain your observations.
Answer:
The temperature readings in both clinical and digital thermometers are the same.

Question 21.
What is value of one small division on the Celsius scale?
Answer:
Reading the Celsius scale on thermometer.

1. Temperature difference is indicated between two bigger marks.
2. Between these two bigger marks divisions are there.
   
3. Suppose two consecutive bigger marks differ by one degree and there are 10 divisions between them then one small division reads
   1/10 = 0.1°C
   ∴ The value of one small division on the Celsius scale is 0.1 °C.

Question 22.
How do you measure the temperature of other objects?
Answer:

1. To measure the temperature of other objects there are other thermometers.
2. One such thermometer is known as the laboratory thermometer used to measure temperature of water.
3. Six’s maximum and minimum therometer is used to measure maximum and minimum temperatures of a day.

Question 23.
Can you make use of laboratory thermometer like a clinical thermometer?
Answer:

1. We should take some hot water in a beaker, dip thermometer in it for one minute.
2. Record the temperature while the thermometer is in water.
   
3. Take out the thermometer from water. Observed the mercury thread carefully.
4. As there is no kink in the laboratory thermometer mercury falls down in the glass tube of its own when taken out of the water. So we cannot use a laboratory thermometer like a clinical thermometer.

Question 24.
Measure the temperature of different students by touching them and noting in the clinical thermometer.
Make sure that you have cleaned the thermometer before each measurement.

Compare the values in the table after completion of recording.
a) What do you observe in the table?
b) Are the estimated temperature and measured temperature same?
c) Is the body temperature of every person 37 °C (98.6 °F)?
d) What is the average body temperature of your friends?
The average body temperature of a large number of healthy persons is known as normal temperature (98.6 °F).
Answer:
The student is advised to do this work as a project work.

Question 25.
Some of the objects are given in the table. Mark these objects as hot or cold. What is your conclusion?

Answer:

1. We see that some objects are cold and some are hot.
2. We also know that some objects are hotter than others while some are colder than
   others.
3. To decide which object is hotter than the other, and which object is colder than the other.
4. We need a reliable method to decide the hotness/coldness of an object.
5. Generally, hotness or coldness is expressed in terms of temperature.
6. Temperature is a measure of the degree of hotness or coldness of an object.

Question 26.
How can find out the hotness or coldness of a substance by touch? Explain.
Answer:

1. By touching with our hands, we can guess whether a cup of milk is still worth sipping or has become too cold, whether milk is hot enough for making curds etc.
2. But estimating temperature with our hands can, sometimes mislead or confuse us.
3. Take some cold water, luke-warm water and hot water in three different vessels.
   
4. Immerse your left hand in the cold wa¬ter vessel and right hand in hot water vessel simultaneously. Wait for two or three minutes.
5. Take off both your hands and dip them in the luke-warm water vessel.
6. Though both hands are in the same glass of water, one hand feels it cold and the other feels it hot! Look how our hands are confused!
7. We can not exactly decide the hotness/coldness of a substance just by touching it?. It is not possible to guess the hotness of a substance only on the basis of feel/touch.
8. It is certain that water in different tubs has different degrees of hotness which can¬not be exactly determined simply by touching.

Question 27.
How do we establish by experiment that liquids expand due to heat?
Answer:

1. We should take a flat bottom flask and fill it with coloured water.
2. Fix a cork, having a capillary tube, in the mouth of flask such that level of water is as shown (fig).
   
3. We should place the flask in a metal trough.
4. We should pour boiling hot water into the trough and carefully observe the level of coloured water. The level rises.
5. If we take the flask out of the trough and keep it outside for some time, the level of coloured water decreases.
6. In the above activity we see that water expands on heating and contracts on cooling.

Question 28.
Record your observations in the following.

Answer:
Do the above observation independently.

Question 29.
Did you ever bathe with cold water during winter? What happens?
Answer:

1. I have taken bathe with cold water during winter.
2. My body shivered with chill.

Question 29.
What do you do to protect yourself from cold?
Answer:

1. I wear woolen and dark coloured clothes to protect myself from cold.
2. I will cover my body with a blanket to protect myself from cold in the night.

Question 30.
How do you get hot water in winter?
Answer:
By heating water, I get hot water in winter.

Question 31.
Generally we heat water to get hot water. How do you heat water? What sources do you use?
Answer:
By converting electrical energy, chemical energy and mechanical energy into heat we heat water. We use electric heaters, gas stoves and solar heaters to heat water.

Question 32.
Give examples of conversion of energy from one form to another.
Answer:

1. Different kinds of energies can be converted to heat.
2. In the same way heat energy can be converted to other forms of energy.
3. We have heard that in a thermal power station, heat energy is converted to electrical energy.
4. In a steam engine, heat energy is converted to mechanical energy which helps in moving the engine.
5. In electrical heater electrical energy, in gas stove chemical energy and in solar heaters solar energy are converted to heat.

Question 33.
What are the liquids used as thermometer liquids?
Answer:

1. Mercury is used as liquid for indicating temperature in thermometers.
2. Apart from Mercury we also use alcohol as thermometer liquid.

Question 34.
Describe the construction of a thermometer with a neat diagram.
Answer:

1. At one end of the tube we observe a bulb. It is filled with Mercury.
2. The other end of the tube is sealed after removing air from it.
   
3. We find a scale which is marked to express temperature in degree Celsius.
4. We read the temperature with the help of these markings.
5. The readings range from 0° to 100°
6. This arrangement of the marks is called scale of temperature.
7. All thermometers are based on the fact that matter expands on heating.

Question 35.
Draw a neat diagram of Six’s maximum and minimum thermometer. What is its importance.
Answer:
1) The maximum (highest) and minimum (lowest) temperatures of a day are measured by a thermometer called the Six’s maximum-minimum thermometer.

Question 36.
How do you use a thermometer? Write an example.
Answer:

1. To find the temperature of an object, the bulb of the thermometer needs to be in close contact with that object.
2. Watch the shiny line of mercury in the tube. .
3. The highest point on the scale, at which the rise of mercury stops, shows the temperature of the object.
4. Example: To find the temperature of your palm, place the bulb of thermometer in contact with palm for two minutes and see the mercury rise.
5. When mercury stops rising and its level becomes steady, note the position of its upper end.
6. This is the temperature of your palm.

Question 37.
If markings on thermometer are wiped out, how do we create new markings?
Answer:

1. Take some ice in a beaker. Immerse a thermometer in ice for two minutes. Mark the Mercury level. Now let the ice melt.
2. The level of Mercury remains same while ice melts. This means that temperature is constant.
3. This constant temperature at which ice melts is called melting point of ice and mark it 0 °C.
4. Take some water in a beaker. Immerse the thermometer in it and start heating the water. It will start boiling while getting converted into steam.
5. Mercury level starts rising and reaches a point beyond which it doesn’t rise. Mark the level of mercury at this point.
6. Observe the constant level at which Mercury stays while water is boiling, this constant temperature is called boiling point of water. We mark the level of mercury at this point as 100 °C.
7. Thus temperature at which ice melts or water boils is constant. These values are fixed as 0 °C and 100 °C respectively. Like water, all substances in pure form melt and boil at certain fixed temperatures.
8. To create a scale, we need two fixed points. Let us choose the melting point (0 °C) and boiling point (100 °C) as two fixed points for the scale of thermometer. Now divide the distance between these two points on the thermometer into 100 equal parts.
9. Each of the 100 equal parts represents 1 °C. We further divide 1 °C into 10 small divisions. It can be read as 1/10 = 0.1 °C.

Question 38.
Feel the body temperature of some of your friends by placing your hand on their forehead. Estimate the temperature and record it in the table.

Answer:
The student is advised to do this with the help of the teacher.

Question 39.
How do you note the temperature of water taken in a beaker?
Answer:

1. Take some tap water in a beaker.
2. Dip the thermometer in water so that the bulb is immersed in water but does not touch the bottom or side of the beaker.
3. Hold thermometer vertically, wait till the mercury thread becomes steady.
4. Note the reading. That is the temperature of water at that time.

Question 40.
Observe the diagram and answer the following questions.

1. What is the aim of the experiment?
2. Write down the apparatus required.
3. What are your observations?
4. Where do you find this type of phenomenon in your daily life?

Answer:

1. Liquids expand on heating.
2. A flat bottom flask, cork, coloured water, metal trough, boiling hot water.
3. Water expands on heating and the level in coloured water is increased.
4. We can observe this phenomenon in the thermometer in our day to day life.

Question 41.
Read the paragraph and answer the following questions:
Heat is a type of Energy. It is transferred from hot object to cold object. We know the hotness and coolness of an object due to the transformation of energy. It is called “Heat”. If you want to heat the water with electric heater, Electric Energy is turned into Heat Energy. If you heat the water on gas stove, Chemical Energy is turned into Heat Energy.
i) What is Heat?
ii) How is heat transferred from one object to other?
iii) Which equipment is used to turn Electric Energy into Heat Energy?
iv) When we heat water on the gas stove, which energy is turned into Heat Energy?
Answer:
i) It is a form of energy. The energy which makes an object appear hot or cold is called heat.
ii) Heat flows from an object at high temperature to another at lower temperature.
iii) Electric heater.
iv) Chemical energy.

Question 42.
What questions would you ask the doctor to clarify your doubts on the usage of the thermometer?
Answer:

1. Why do we use thermometer in our daily life?
2. Why is mercury used in thermometers?
3. How do we measure the temperature in thermometer?
4. How many types of scales are marked on the thermometer?

Question 43.
Read the paragraph given below and answer the following questions.
Temperature is a measure of the heat energy in a body. We use thermometers to measure temperature. Mercury is a good conductor of heat and is a liquid at room
temperature. It is used in most thermometers. In some thermometers, alcohol is used. Alcohol can record very, low temperatures.
i) What is temperature?
ii) Name the device used to measure the temperature.
iii) Name the liquid used commonly in the thermometers.
iv) Name the liquid used in thermometers to measure low temperature.
Answer:
i) Temperature is a measure of heat energy in a body.
ii) The device used to measure temperature is thermometer.
iii) Mercury is the liquid used in thermometers.
iv) Alcohol is used in thermometers to measure low temperature.

Question 44.
Observe the table and answer the following questions.

i) Name the month and date when the minimum temperature was recorded.
ii) On which date was the maximum temperature recorded?
iii) Between which two consecutive months, the difference in temperature was the highest?
iv) In which month people could most likely have used air-conditioner to get relief from heat?
Answer:
i) 1st January, 2019.
ii) 15th May, 2019
iii) April and May
iv) In May month

SCERT AP Board 7th Class Social Solutions 18th Lesson Caste Discrimination and the Struggle for Equality Textbook Questions and Answers.

AP State Syllabus 7th Class Social Studies Solutions 18th Lesson Caste Discrimination and the Struggle for Equality

7th Class Social Studies 18th Lesson Caste Discrimination and the Struggle for Equality Textbook Questions and Answers

Improve Your Learning

Question 1.
What is the difference between being punished for a mistake and being discriminated against? Was the child Ambedkar being punished or discriminated against?
Answer:
There is a lot of difference between being punished for a mistake and being discriminated against. Punishment is given to those who commit a mistake or a wrong without showing any discrimination. More than that punishment is corporal but discrimination has an effect on one’s psyche, dignity, and character. But the discrimination is shown based on one’s birth and social status. Punishing those who commit wrongs defends the rights of other people. But discrimination denies the people their freedom, equality, respect, and dignity of the victims.
The child Ambedkar did no wrong, so he was not supposed to be punished. But he was discriminated against because of his caste and thus he was denied social equality, self-respect, and dignity.

Question 2.
Do you think it is possible to make friends across castes – what kind of problems will you have to overcome this?
Answer:
It is possible to make friends across states. I have no problems.

Question 3.
Our Constitution abolished the practice of untouchability and declared it a crime.
Do you think it has been fully abolished in practice?
Answer:
Article No: 17 abolished the practice of untouchability and declared it to be a crime. But in practice, it has not been fully abolished from society.
One of the main reasons for this is that attitudes change very slowly. Even though persons are aware that discrimination is against the law, they continue to treat people unequally on the basis of their caste, religion, disability, economic status, and gender. It is only when people begin to believe that no one is inferior and that every person deserved to be treated with the dignity that present attitudes can change.

Question 4.
Why do you think people want to marry within their caste? Will this help to preserve caste inequality?
Answer:
A group of people, who follow some common rules and customs, worship the common deities, follow the same profession or work, and are bonded together said to be one caste Every caste has its own identity its own rules and customs, its own deities. Each case wants to keep its own identity by keeping itself into an undivided element. They don’t want to mix with others. They feel it as contamination of caste if their young ones marry other caste people.
If people go on negating inter-caste marriages the caste system keeps on strengthening itself. As it goes on strengthening all the social evils that remain alive, Thus it will help to preserve caste inequality.

Question 5.
Savitri Bai Phule was the first headmistress of the country’s first school for girls in Pune. She devoted her life to educating Dalits. She started a night school for agriculturists and laborers. She died while serving plague patients.
Answer:
She was a social reformer along with her husband Jyothi Rao Phule, who played an important role in women’s rights in India during British, rule. She pioneered the campaign for women’s education, staging the first school for girls at Pune in 1848. Savitribai was the first female teacher of the first women’s school in India. In 1852, she opened a school for untouchable girls. Even though she faced many problems, she continued her teaching for the welfare of Dalits.

SCERT AP Board 7th Class Social Solutions 6th Lesson Africa Textbook Questions and Answers.

AP State Syllabus 7th Class Social Studies Solutions 6th Lesson Africa

7th Class Social Studies 6th Lesson Africa Textbook Questions and Answers

Improve Your Learning

Question 1.
From Europe, which sea does one have to cross to reach northern Africa?
Answer:
One has to cross the Mediterranean sea from Europe to reach northern Africa.

Question 2.
State three difficulties that the Europeans faced in reaching the interior parts of Africa.
Answer:
The three difficulties that the Europeans faced in reaching the interior parts of Africa are:

1. Besides attempting to build their colonies in Africa, the Europeans continued to explore the interior of the continent.
2. They travelled to the source of the Nile in the north.
3. In the west, they explored the entire valley of the Niger and in the south, they moved northwards from Cape Town.
4. There they explored the region around the river Zambezi.

Question 3.
Name the two large deserts of Africa.
Answer:

1. The Sahara Desert is in Africa. It extends to Mauritania, Mali, Niger, Chad, Sudan, Morocco, Tunisia, Algeria, Libya, Egypt, Ethiopia and Somalia.
2. The Kalahari Desert extends in Namibia, Botswana and Angola in South – West of Africa. These deserts are not suitable for agriculture due to scanty rainfall and infertile soils.

Question 4.
a) The zone between the Tropics of Cancer and Capricorn is the zone of ………… climate.
Answer:
Hot.

b) The main vegetation of Savanna lands is …………
Answer:
Grass.

c) The two main rivers emptying themselves into the Atlantic ocean are ………. and ………….
Answer:
Congo, Nigeria.

d) The regions in Africa to the north of the Tropic of Cancer and to the south of the Tropic of Capricorn are of …………. climate.
Answer:
Cold.

Question 5.
Two political maps of Africa have been given in the chapter. Compare the two to find out which European country controlled the present day countries of Nigeria and Zimbabwe?
Answer:
Britain controlled the present day countries of Nigeria and Zimbabwe.

Question 6.
Name two countries of Africa where equatorial forests are found.
Answer:

1. Republic of Congo, Gabon
2. Cameroon.

Question 7.
What goods did Europeans trade with Africa? What kind of agricultural products did they promote for trade purposes?
Answer:

1. Gold, copper and diamonds were the Europeans traded with Africa.
2. Tea, coffee, rubber, tobacco were the agricultural products they promoted for trade purposes.

Question 8.
Who benefited from the slave trade? Why did America need slaves?
Answer:
In the 16th century, many Europeans began migrating to America and started cultivation there. There was plenty of land in America, but not enough people to work in the fields. It was to fulfil this need for additional working hands in America that the slave trade from Africa began. America benefited a lot from the slave trade.

Question 9.
How can you say that the slave trade is highly heinous?
Answer:
The slave trace (Trans Atlantic Slave Trade) is one of the most heinous crimes committed against people over the course of more than 400 years. Millions of Africans were turned from their homes, were deported to the American continent and sold as slaves.
The slave trade resulted in the loss of human life. The savage nature of the slave trade led to the destruction of families, individuals and cultures and the vestiges of the immense loss of human capital to the African continent are still felt to this present day.

Question 10.
Read the last para of this lesson Africa and comment on it.
The foreign companies do bring in new technologies and investments into the mining and processing industries, thus creating employment for the local people. However; they use cheap labour to make huge profits which are taken away from the African people most of these companies are also careless about environmental protection and have caused immense damage to the natural environment. This has affected the quality of land and life of the people adversely.
Answer:

1. Africa is very rich in minerals like coal, copper, tin, etc.
2. So many of the European countries and their companies to this day control much of the mineral resources of even the independent African countries.
3. The foreign companies do bring in new technologies and investments into the mining and processing industries, thus creating employment for the local people.
4. They are using their cheap labour to make huge profits and exploiting the mineral resources.
5. Most of these companies have caused immense damage to the natural environment which has affected the quality of land life of the local people adversely.
6. Thus, we can say that the foreign companies are exploiting the mineral wealth of Africa irrespective of the local people’s welfare.

AP State Syllabus AP Board 7th Class Science Important Questions Chapter 11 Respiration in Organisms

AP State Syllabus 7th Class Science Important Questions 11th Lesson Respiration in Organisms

7th Class Science 11th Lesson Respiration in Organisms Important Questions and Answers

Question 1.
What is breathing?
Answer:
The process by which air goes in and out of our body is called breathing.

Question 2.
What is inspiration and expiration ?Explain the term ‘respiration rate’.
Answer:

1. The process of breathing in air is called inspiration and that of breathing out air is called expiration.
2. The number of times we breathe in and breathe out air in a minute is called the respiration rate.

Question 3.
What does our breath contain?
Answer:

1. We know that we inhale and exhale air.
2. The exhaled air is warm and has moisture in it.
3. What we do not know is about the gases our body takes from the inhaled air and throws out in exhaled air.
4. We know that air is a mixture of several gases not only Oxygen and Carbon dioxide, there are others as well. Air also contains several suspended particles.
5. We inhale all these.
6. We exhale Carbon dioxide, Oxygen, Nitrogen and other gases.

Question 4.
How does a fish breathe?
Answer:

1. Observe fishes in an aquarium. Fishes continuously open and close their mouth in water.
2. Why do the flaps on both sides of the head alternately open and close?
   
3. If you look below the flaps, you will see gills. These are the respiratory organs of the fish.
4. The water that enters the mouth flows through both the gills as it comes out of the flaps.
5. The gills absorb the oxygen that is dissolved in the water. This oxygen is carried to different parts of the body.

Question 5.
Describe how does a frog take its breathe.
Answer:

1. We know that frog is able to stay on land, in water and even underground.
2. To breathe on land it has lungs while it goes deep underground and sleeps twice every year, its moist skin takes over the function of its lungs.
   
3. In baby frogs or tadpoles there are special organs like that of fishes called gills.
4. These gills help them to breathe in water by taking in the air dissolved in water.
5. Tadpoles of the frog live only in water but the frog lives either on land or in water. Sometimes you may see frogs under the soil also.
   

Question 6.
Explain the breathing process in cockroach.
Answer:

1. A cockroach has small openings on the sides of its body.
2. Other insects have similar openings.
   
3. On the underside of the cockroach in each segment, there are small holes which are connected through respiratory tubes in a network.
4. These help the cockroach to breathe. These holes are called spiracles.
5. The network of respiratory tubes called trachea take air from these spiracles, circulate it throughout the body, collect it back and send it out through these spiracles.
   
6. To know more about this process you may observe a live cockroach by keeping it covered by a transparent bottle or glass.

Question 7.
Describe how does an earthworm breathe.
Answer:

1. Earthworms breathe through their skin.
2. It is thin and moist with minute holes.
   
3. Through the skin, air passes in and out.
4. The earthworm thus breathes through its whole body surface.

Question 8.
How do plants respire?
Answer:

1. In human beings gaseous exchange with the surroundings takes place through nose and mouth.
2. We know the parts in plants that help in gaseous exchange.
3. They are stomata present on surface of leaves and lenticels present on the surface of stems.
4. They respire through them.

Question 9.
At what time plants respire and photosynthesize?
Answer:

1. In day time plants respire as well as photosynthesize.
2. At night only part of the process of photosynthesis takes place and carbon dioxide is not used up completely by this process.
3. Respiration continues at night also.

Question 10.
What is use of oxygen in hospitals?
Answer:

1. You may have heard of big hospitals keeping cylinders filled with oxygen.
2. When a person has breathing problems he is given oxygen.
3. An oxygen mask is fitted to the nose and mouth of the person and a rubber tube connects the mask to the oxygen cylinder.
4. Sometimes a patient is given oxygen during an operation.

Question 11.
In your opinion does the expiration rate increase or decrease after exercising?
Answer:

1. The air we breathe in fills our lungs that are located in our chest.
2. Exercise and running increase the rate of our breathing.

Question 12.
What happens to your chest when you take a breath?
Answer:

1. Take a length of twine or a measuring tape. Wrap the tape around the chest of one of your friends and measure the width of her / his chest.
   
2. Hold the tape lightly and ask your friend to breathe in and out deeply a few seconds.
3. You find that the chest expands when air is inhaled, it reaches the lungs and chest expands.

Question 13.
What is the difference between inhaled and exhaled air?
Answer:

1. Exhaled air is warm and contains moisture and carbon dioxide.
2. Inhaled air is at room temperature and contains oxygen along with other gases.

Question 14.
How long a person can hold his / her breath? How do you find?
Answer:

1. Use a watch with a seconds needle to time our breathing.
2. If we don’t have a watch, then practice counting at a uniform rate.
   
3. We can measure the time by counting.
4. Close our mouth and close our nose with our fingers so that air cannot pass through it.
5. We can find the time for how long could we keep our mouth and nose closed.

Question 15.
How many breathes do you have in a minute?
Answer:

1. Hold a finger under the nose of one of your friends.
2. The side with the fingernail should face the nostrils.
   
3. Ask your friend to breathe in and out normally.
4. When your friend exhaled your finger felt the warmness of the air.
5. Using this method you can find out how many times your friend inhales and exhales in a minute.

Question 16.
How much air do you breath? Do a simple activity to know it?
Answer:

1. Make a measuring cylinder with a two-litre plastic bottle and 100 ml injection bottle.
2. To do this, pour 100 ml of water at a time in the bottle and mark the water level after each addition.
3. Now fill the bottle to the brim and invert it in a bucket or a large container of water.
4. But remember, no air bubbles should remain in the bottle after you invert it.
   
5. Insert one end of a rubber tube into the mouth of the bottle under water.
6. Hold the other end of the tube in your hand. Inhale as much air as you can and blow the air into the measuring cylinder through the rubber tube.
7. Don’t breathe in while blowing the air out.
8. Blow out as much air as you can in a single breath.
9. This air will collect in the measuring cylinder.
10. As a result,-the water level in the cylinder will fall.
    The reduction in water level is equal to the air you breath.

Question 17.
How do you find the gases that are present in our breath? Describe the activity you perform.
Answer:

1. Set up the apparatus shown in Figure (a) for this experiment. Be careful while inserting the glass tube in the cork. It could break. So take the help of your teacher to do this.
   
2. Fill both boiling tubes one fourth with phenolphthalein solution. Mark them A and B.
3. Now repeatedly blow in and suck out air in this apparatus as shown in Figure (b).
   
4. Note the boiling tube in to which air flows when you suck in air.
5. Note the boiling tube through which air flows out when you blow out air.
6. You find that there is a difference between inhaled air and exhaled air.
7. Repeat the experiment by replacing the boiling tubes with lime water filled one fourth in them.
8. You will find that the lime water in the tube through which exhaled air passed turned milky.
9. This indicates that the exhaled air contains carbon dioxide.
10. The table given here under shows the components in the inhaled air and exhaled air.
    

Question 18.
How can you find out the respiration in plants by an experiment?
Answer:

1. Take a conical flask. Fit a two-holed rubber cork tightly into its mouth and insert glass tubes into the two holes.
2. Fit a rubber tube on one of the glass tubes and a funnel on the other. If the funnel does not sit tightly on the glass tube, make a funnel with an ink dropper.
3. Fill a test tube about one-fourth with lime water and dip the rubber tube into it.
4. Now add water to the funnel drop by drop. Keep adding water till the conical flask is filled one-fourth with water. Observe the test tube carefully while you add water.
5. You find no change in the colour of lime water.
6. Now remove the water from the conical flask and put some flowers and buds in it. Fit a cork on the flask and let it stand for half an hour.
7. Now add water drop by drop to the conical flask through the funnel as you did in the previous experiment. Look carefully at the test tube while doing so.
8. The lime water turns milky indicating the release of carbon dioxide.
9. This is how plants respire. They take oxygen and release carbon dioxide.

Question 19.
How do you find respiration in sprouted seeds?
Answer:

1. Take sprouted seeds is the conical flask.
2. Pour water drop by drop in to the funnel through the funnel.
   
3. The released gases are allowed to pass through lime water.
4. Lime water turns milky indicating the release of carbon dioxide.
5. Sprouted seeds respire taking oxygen and releasing carbon dioxide.

Question 20.
Write a note on the discovery of carbon dioxide.
Answer:

1. The first step towards trying to find out what air contained was carried out by Von Helmont.
   
2. He conducted an experiment of burning charcoal which leads to the formation of ash.
3. He found the weight of ash to be much less as compared to charcoal.
4. On the basis of this, he concluded that the decrease in mass was due to the formation of an invisible substance which he named “gas”.
5. In the year 1756, Joseph Black studied this gas in more detail.
   
6. He found that when limestone is heated or reacted with acids, it gives rise to a gas which he called “fixed air”.
7. He studied several properties of this gas. One of the properties was, lime water turned milky when this gas was passed through it.
8. Now we know this gas as carbon dioxide.

Question 21.
How is oxygen discovered? Write the history of its discovery.
Answer:

1. After nearly two decades of discovery of carbon dioxide, oxygen was discovered.
2. Joseph Priestley, published his“Experiments and observations on different kinds of air” and was the first to prove the different qualities of the gases released by plants and the one’s exhaled by animals (mice).
   
3. He discovered that, although a candle burned out in a closed container, when he added a living sprig of mint to the container, the candle would continue to burn.
4. At the time, Priestley did not know of Oxygen, but he correctly concluded that the mint sprig “restored” the air that the burning candle (or mice which he used in a similar set of experiments) had spoiled.
5. Priestley shared his observations with Lavoiser.
   
6. Lavoiser had also conducted several experiments on atmospheric air and knew that it contained many gases, and he identified Priestley’s discovery as the active component of air for which he had been searching.
7. He called it oxygen (Greek: acid former), in the belief that all acids contained it.

Question 22.
Do plants respire?
Answer:

1. Plants respire like us.
2. But it is difficult to observe this through experiments.
3. Both plants and animals use oxygen during respiration.

Question 23.
Read the table and answer the following questions.

1. Which animals respire through the trachea?
2. Why does fish respire only in water?
3. In how many ways does frog respire?
4. Give some more examples for animals that respire with lungs.

Answer:

1. Scorpion, Cockroach, Grasshopper.
2. Gills are the respiratory organs of the fish. The gills absorb the oxygen that is dissolved in water. Hence, fish respire only in water.
3. Gills, Lungs, Skin.
4. Frog, Monkey, Man.

Question 24.
Name the respiratory organs of the following animals,
a) Fish b) Earthworm
Answer:
a) Fish ——– Gills.
b) Earthworm ——– Skin.

Question 25.
Read the table. Answer the questions given below.

a) Which gas is more in inhaled air?
b) What changes do you observe in the percentage of carbon dioxide in the exhaled air? Where does it come from?
c) How much Oxygen is retained in our body?
d) Which gas is more useful in our respiration process?
Answer:
a) Nitrogen
b) The volume of carbon dioxide is increased. CO₂ is released during respiration.
c) 45 ml
d) Oxygen.

Question 26.
Latha’s teacher conducted an experiment in the classroom. Look at the picture and answer the following questions.

1. What is the aim of this experiment?
2. Which equipment is required to conduct this experiment?
3. Which gas is released during the experiment?
4. What other material can be used in this experiment instead of seeds?

Answer:

1. To prove that respiration takes place in plants.
2. Conical flask, a two-holed rubber cork, test tube, funnel, rubber tube and lime water.
3. CO₂ (Carbon dioxide)
4. Moong, Bengal gram.

AP State Syllabus AP Board 7th Class Science Important Questions Chapter 7 Electricity – Current and Its Effect

AP State Syllabus 7th Class Science Important Questions 7th Lesson Electricity – Current and Its Effect

7th Class Science 7th Lesson Electricity – Current and Its Effect Important Questions and Answers

Question 1.
What are Series and Parallel electric circuits?
Answer:
A) Series circuits:

1. In a series circuit, electricity has only one path to flow through.
2. All the electrical components are connected in this path.
3. If any one of them is removed or is not functioning properly, the circuit will be incomplete.

B) Parallel circuits:

1. A parallel circuit has more than one path for the flow of electricity.
2. Each bulb in the circuit is connected in a separate path through which electricity can flow.

Question 2.
Describe the effect of connecting electrical cells in series. How would you connect them in series?
Answer:
Connecting Electrical cells in series:

1. Take a dry cell and torch bulb.
2. Connect the bulb to a cell using copper wires shown in figure-a. Observe the intensity of light.
   
3. Now take one more dry cell and connect two cells as shown in figure-b.
   
4. In this method the positive terminal of the first cell and the negative terminal of the second cell are connected to the bulb.
5. .When the cells are connected in series more electricity flows in the circuit and the bulb glows with greater brightness.

Question 3.
Describe the connection of cells in parallel. Draw the circuit diagram also.
Answer:
Connecting Electric Cells in Parallel:

1. Take three dry cells and connect them as shown in figure-a.
   
2. That is all the positive terminals of the three cells are connected together and all the three negative terminals are connected together.
3. These three positives and three negatives are connected together to a bulb.
4. There is no difference in the intensity of the bulb glow compared to that in the case of only one cell.
   

Question 4.
How are electric bulbs connected in series? Where do you find such connections in your daily life? What is the disadvantage with this arrangement?
Answer:
Connecting electric bulbs in series:

1. Connect three torch bulbs in series as shown in figure.
   
2. Connect this to a dry cell. Observe the brightness of each of the three bulbs.
3. Now connect one more dry cell in series with the first cell.
4. Observe the brightness of each of the bulb.
5. Then connect one more dry cell in series with the first two cells. Again observe the bulbs. The brightness of the bulbs increases with the addition of cells.
6. In series connection of bulbs, if one bulb gets fused, all the other bulbs in the series will stop glowing.
7. It means that if one bulb is disconnected the other bulbs do not glow. This is the disadvantage.
8. This can be observed in serial bulbs used in decorative items at the time of marriages and other festivals.

Question 5.
a) How are electric bulbs connected in parallel?
b) What is, the advantage with this type of connection?
c) Where do you find such connections?
Answer:
Connecting bulbs in parallel:
a)

1. Connect three bulbs in parallel as shown in figure.
   
2. That is, one end of each of the three bulbs are connected to one wire.
3. The other ends of the three bulbs are connected to another wire.
4. These two wires are connected to a cell. All the three bulbs glow dimly.
5. Now disconnect one of the bulbs.

b)

1. It means that if one bulb is disconnected the other bulbs continue to glow.
2. This is the advantage with this type of connection.
3. This can be observed in our household electric circuit. All components in our houses are connected in parallel.

Question 6.
What are the advantages of using tube lights and compact fluorescent lamps.
Answer:

1. Wastage of electricity can be reduced by using fluorescent tube lights in place of the bulbs, as shown in figure, (a).
   
2. Compact Fluorescent Lamp (CFLs) shown in figure, (b) also reduces wastage and can be fixed in ordinary bulb holders.
   
3. The ISI mark of a lamp ensures that the appliance is safe.

Question 7.
What is an electric fuse? Explain its importance. How does it work?
Answer:
Electric Fuses:

1. When excessive electric current flows through a circuit the wires or the appliances may get heated and can catch fire.
2. To avoid fire, a safety device known as a fuse is connected in series in the circuit.
3. A fuse is a small piece of wire as shown in figure.
   
4. It is made of a special alloy that gets heated quickly and melts.
5. If the current in the circuit is too high, the fuse wire gets hot and melts.
6. This leaves a gap in the circuit. Automatically the circuit is broken and flow of electricity is stopped.
7. This protects appliances from getting burnt due to the passage of too large a current through them.

Question 8.
What is a Miniature Circuit Breaker (MCB)? What is its advantage? For which mark should we look at it?
Answer:
Miniature Circuit Breaker (MCB):

1. These days Miniature Circuit Breaker (MCB) is increasingly being used in place of fuses.
2. These are switches which automatically turn off when current in a circuit exceeds the safe limit.
3. It has a switch which goes OFF automatically if there is overheating.
   
4. This breaks the circuit. If we turn them on, the circuit is once Miniature Circuit again complete.
5. The advantage miniature circuit breakers have over fuses is that they can be reset (manually or automatically) to restore normal operation, whereas fuses need to be replaced after every single operation.
6. The MCB can be reset by hand and the circuit becomes complete once again.
7. Look for ISI mark on MCBs.

Question 9.
What are the inventions of Michael Faraday?
Answer:
Michael Faraday (1791-1867): Michael Faraday observed that by moving a magnet in and out of a coil we can make electric current flow through the coil. Using this he built the first electric generator or dynamo in 1831. He also invented the transformer.

Question 10.
What is the importance of symbols? What role do they play in our life?
Answer:

1. We know about symbols. We do indicate to our teacher that we wish to go out to drink water.
2. We know the signs for addition, subtraction, multiplication and division.
3. We might have used the symbols for ‘greater than’, ‘less than’, ‘equal to’ etc.
4. Symbols play an important role in our life.
5. They convey precise meaning with few descriptions.
6. Some common electric components can be represented by standard symbols.

Question 11.
What happens to the electric bulb when the current is passed?
Answer:

1. The bulb becomes hot when we put it on for some time.
   
2. It is the filament of the bulb that heats up due to current flowing through it.

Question 12.
What do you understand by the term ‘the filament of an electrical appliance’?
Answer:

1. We have seen an electric iron, electric cooker and electric heater.
   
2. All these contain a coil of wire made up of Nichrome.
3. This coil is called a filament of the appliance.

Question 13.
What happens when electrical appliances like electric iron, electric heater etc., are switched on?
Answer:

1. We have noticed that when these appliances electric heater, electric iron are switched on, their filaments become red hot and give out heat.
2. The amount of heat produced in a wire depends on its materials, length and thickness.
3. Thus, for different requirements, the wires of different materials, lengths and thicknesses are used.

Question 14.
What happens when an electric current passes through wires used for making electric circuits and through the elements of some electric appliances?
Answer:

1. The wires used for making electric circuits do not normally become hot.
2. On the other hand, the elements of some electric appliances become so hot that they are easily visible.
3. The filament of an electric bulb gets heated to such a high temperature that is starts glowing and giving out light.

Question 15.
Describe how can you make your own cell. Explain how do you test the working condition of that cell.
Answer:

1. We will need a few things to make a cell.
2. First get two injection bottles. Then cut two 3 cm long bits of thick copper wire. Use sandpaper to scrape about 1 cm of the coating off both ends of the wires.
3. Break open a discharged dry cell and remove its outer metal covering (made of Zinc). Cut two 2 mm wide and 3 cm long strips from this zinc plate.
4. Insert the copper wires and zinc strips separately into the rubber caps of the injection bottles as shown in Fig.
   
5. Ensure that the copper wires and zinc strips do not touch each other.
6. Now take a wire and connect the zinc plate of one bottle with the copper wire of the other bottle.
7. Fill both bottles with sulphuric acid. Carefully close the bottles with the caps in which the copper wires and zinc strips are inserted.
8. The cell is ready. To test its working take a LED.
9. Attach two wires to its two terminals. Touch the wire from one terminal to the copper wire of the first bottle and the wire from the other terminal to the zinc plate of the second bottle.
10. The LED lights up. It means the cell is working.

Question 16.
What can you see inside a dry cell when it is cut open?
Answer:

1. With the help of your teacher cut open a dry cell.
   
2. Observe the chemical components in the dry cell.
3. Inside a dry cell there are certain chemicals which react with one another to produce electric energy.

Question 17.
Think of the main use of electrical appliances and write their names in a table.
Answer:

Question 18.
How is electricity supplied to our houses ? Are we getting it free of cost?
Answer:

1. Most of the electricity that we use at home and at school is alternating current.
2. The main electricity that is supplied to our houses comes from power stations and sub-stations distribute electricity.
3. Electricity is not free of cost.
4. We have to pay for it according to how much we consume.

Question 19.
How can you know the current consumed in your house?
Answer:

1. We notice that a person belonging to the electricity department, the meter reader, visits houses every month and takes the meter readings.
   
2. If we look at the meter in our house we will notice a wheel that goes around and the numbers in the window keep changing.
3. Modern meters have digital displays.

Question 20.
What does the term ’one unit’ mean? How is the usage of electricity measured?
Answer:

1. If we look at the bulbs used in our home, we will notice that they are marked in watts 25 W, 40W, 60W, 100W.
2. The wattage measures how ‘powerful’ the bulb is.
3. The brighter the bulb, the higher its wattage and the more the electricity used by it.
4. 1 kilowatt (KW) is 1000 watts (W).
5. When any appliance of 1 Kilo Watt is used for one hour, it uses up one Kilo Watt – hour (KWH) or ‘one unit’ of electricity.
6. If it runs for two hours it will use up two units of electricity.

Question 21.
Draw a neat diagram of the dry cell and label its parts.
Answer:

Question 22.
Describe the construction of a dry cell.
Answer:
Description of a dry cell:

1. A dry cell consists of a container made up of zinc metal.
2. The container also serves as the negative terminal in the centre.
3. A carbon (graphite) rod with a metal cap serves as a positive terminal.
4. The carbon rod is surrounded by a mixture of carbon particles and a chemical called ammonium chloride.
5. The cell is sealed from the top.
6. The dry cell can supply electric current in a circuit for a certain time.
7. After that/its chemicals get exhausted and it cannot be used any more.
8. Dry cell converts chemical energy into electrical energy.

Question 23.
Write the symbols of some common electric components and describe their use.
Answer:

Question 24.
Draw a simple switch to close the circuit. For that draw the circuit diagram.
Answer:

1. See figure (a). A bulb, battery and switch are connected as shown.
2. Can we make this drawing simpler using symbols ?
3. The picture of circuit using symbols is called a circuit diagram.
4. Figure (b) shows a circuit diagram of the same circuit as shown in figure (a).

Question 25.
What is a circuit diagram? Explain it appreciating the simplification.
Answer:
Circuit Diagram: The picture of a circuit using symbols is called a circuit diagram.

1. There should be a source, which is one or more electric cells (battery).
2. The switch can be placed anywhere in the circuit. If the switch is in the ON position, the circuit is complete from the positive terminal of the battery to its negative terminal.
   
3. The circuit is then said to be closed and the current flows throughout the circuit constantly.
4. The wires should not have any discontinuity (gaps).
5. When the switch is in the OFF position, the circuit is incomplete. It is said to be open. No current flows through any part of the circuit.
6. Observe the sequence in which the cell, bulb and switch are connected in the circuit.
7. The sequence of components is as follows:
   Positive terminal of the cell → Wire → Switch → Wire → Bulb → Wire → Negative terminal of the cell

Question 26.
Why does the bulb glow brighter and brighter when electric cells are connected in series?
Answer:

1. The electricity can flow through one path when electric cells are connected in series.
2. Addition of a cell in such a circuit adds strength to the electricity flowing.
3. As more electricity flows into the bulb its glow becomes brighter.

Question 27.
Does electric bulb in your house glow with dry cell? Why?
Answer:

1. The electric bulb in our house does not glow with dry cell.
2. The electric bulb in our houses glows with the supply of A.C. at high voltage.
3. Dry cell supplies only D.C. at a low voltage.

Question 28.
Are the cells used in a torch light and wrist watch the same?
Answer:
They are not the same.

Question 29.
What is the reason for connecting electric bulbs in parallel in household electric appliances?
Answer:

1. In the house every bulb should glow independently without depending upon the working condition of other bulbs.
2. This is possible only with parallel connection.
3. So electric bulbs or electric appliances are connected in parallel in household electric connections.

Question 30.
How do we get a battery?
Answer:
By connecting small cells in series we get a battery.

Question 31.
The meter reading in Ayub’s house in January is 400 units, February 580 units. Calculate how much his parents would have to pay towards electricity bill of February. The unit cost is Rs. 3.05.
Answer:

Question 32.
Suppose in a house there are four bulbs of 100 W each, six of 60 W each and six of 40 W each. All of them are used for two hours a day. How many units of electricity will be used up in 30 days? How much will they have to pay at Rs. 2.80/- per unit.
Answer:

1. Total power used = (4 × 100 W) + (6 × 60 W) + (6 × 40 W) = 1000 W = 1 KW
2. Total power used every day = 2 hrs × 1 KW = 2 KWH
   In 30 days, power used = 2 × 30 KWH = 60 KWH
3. The cost of the power is = Rs. 2.80 × 60 = Rs. 168/-

Question 33.
Why should we use electricity carefully and only when needed?
Answer:

1. Our country faces a shortage of electricity.
2. So wasting electricity means we are depriving someone else of electricity.
3. Our bill also goes up.
4. So use electricity carefully and only when it is needed.

Question 34.
a) Look at the diagram, correct it and redraw.

b) Guess the reasons why the bulb did not glow in the circuit.
Answer:
a)

b)

1. The wires are not properly connected.
2. The battery lost its efficiency
3. The battery is not set properly.
4. The bulb has lost its filament.

Question 35.
Fill the table with suitable symbol of electric components listed in the table.

Answer:

AP State Syllabus AP Board 7th Class Science Important Questions Chapter 4 Motion and Time

AP State Syllabus 7th Class Science Important Questions 4th Lesson Motion and Time

7th Class Science 4th Lesson Motion and Time Important Questions and Answers

Question 1.
Give few examples of motion you observe in day to day life.
Answer:

1. Motion is a common experience in our life. We observe birds flying in air, buses, autos, cars, bullock carts, moving on roads, trains on railway tracks and many other objects around us in motion.
2. Apart from observing motions of objects around us, we ourselves experience motion while we are walking, running, playing, riding a bicycle etc.
3. Similarly, we observe many objects like trees, buildings, display boards, electric poles etc., at rest while we walk to school.

Question 2.
How do you explain the terms motion and rest? Give an illustrative answer.
Answer:

1. We know that the position of the car has changed with respect to the tree in ‘2’ seconds. But there is no change in the position of the tree with respect to its surroundings.
   
2. An object is said to be in motion if it changes its position with respect to its surroundings in a given time.
3. An object is said to be at rest if there is no change in its position with respect to its surroundings in a given time.
4. Thus, we can say that the tree is at rest and the car is in motion while we observe them over a period of time (2 seconds in this case).

Question 3.
Explain the terms uniform and non-uniform motions and define them.
Answer:
Uniform and non-uniform motion:

1. A body is said to be in motion if its position keeps on changing with time (with respect to the observer).
2. But in our daily life we experience certain motions in which, the change in position of objects remains the same for a time interval, in some other motions, the change in position of the object will not be the same for a given time interval.
3. Uniform motion (Definition): If a body covers equal distances in equal intervals of time it is said to be in uniform motion.
4. Non – Uniform motion (Definition): If a body covers unequal distances in equal intervals of time, it is said to be in non – uniform motion.

Question 4.
Explain the types of motion with suitable examples.
Answer:
Types of Motions:

1. When we discuss about motion, it is important to be aware that there exist different types of motions and each type is dependent on a particular situation.
2. Let us consider the following examples.
3. A car travelling along a straight road.
4. Motion of blades of a ceiling fan.
5. Motion of needle in a running sewing machine.
6. Motion of pendulum in an old wall clock.
7. Considering the direction of motion what differences do we notice in above examples?
8. The motions in the above examples are different in terms of direction of motion.
   a) Car is moving in same direction along a straight line.
   
   b) Blades of ceiling fan rotate about a fixed line in a circular path.
   
   c) Needle of sewing machine moves up and down about a fixed point.
   
   d) Pendulum of the wall clock oscillates ‘to’ and ‘fro’ about a fixed point.
   
9. Based on the path taken by the bodies in motion we classify motion of bodies as,
   1) Translatory motion
   2) Rotatory motion
   3) Oscillatory motion

Question 5.
Define rectilinear motion and curvilinear motion.
Answer:

1. Rectilinear motion (Definition): If a body in translatory motion moves along a straight line then motion is called rectilinear motion.
2. Curvilinear motion (Definition): If a body in translatory motion moves along a curved path then motion is called curvilinear motion.

Question 6.
Identify the types of motion in the examples given below.
We notice everyday some motions which are rectilinear and curvilinear at a time. Some examples of motions are given below; Label them as rectilinear (R) or curvilinear (C) or Rectilinear and curvilinear (RC) motions.
1. Seconds hand of a watch. ( )
2. Movement of a train on tracks. ( )
3. Movement of a tape in a tape recorder. ( )
4. Movement of a needle in a speedometer of car. ( )
5. Movement of a bus on hill station road. ( )
6. Motion of coins on a carrom board. ( )
7. Motion of the ball in pin board. ( )
8. Motion of a mango falling from tree.  ( )
Answer:
1. Seconds hand of a watch. ( C )
2. Movement of a train on tracks. ( R )
3. Movement of a tape in a tape recorder. ( C )
4. Movement of a needle in a speedometer of car. ( C )
5. Movement of a bus on a hill station road. ( RC )
6. Motion of coins on a carrom board. ( R )
7. Motion of ball in pinboard. ( RC )
8. Motion of a mango falling from tree. ( R )

Question 7.
Explain Rotatory motion with suitable examples.
Answer:
Observe the following diagrams.


1. What similarity do we find in all the motions?
Answer:
We find all the bodies rotating around an axis.

2. What is the path of motion of each particle of the body that moves?
Answer:
The path of motion of each particle of the body that moves is circular.

3. Is there any change in the position of a body while it is in motion?
Answer:
Except car there is no change in the position of the bodies while they are in motion.
The motion of all these bodies is rotatory motion.

Question 8.
Explain rotatory motion by taking the blades of a fan moving as an example. Define rotatory motion.
Answer:

1. While the blade of a fan is moving, the points A, B, and C on the blade move to Av Br Cj first and then move to A2, B, and C2 position,
2. Thus when a fan is in motion, each point on the blade moves in a circular path around the centre of the fan which is fixed.
3. Here, we observe that the position of a fan is not changing.
   Only the blades of fan are changing their position continuously and moving in circular path around a fixed point.
   
4. The imaginary line passing through this fixed point is called axis of rotation.
5. This type of motion is called Rotatory Motion.
6. Rotatory motion (Definition) : Rotatory motion means that, motion of all particles of a moving body follow a circular path with respect to a fixed centre or axis of rotation.

Question 9.
Explain the terms ‘slow’ and ‘fast motions’.
Answer:

1. We observe many objects in motion in our daily life.
2. In some cases objects move slowly and in other cases they move fast.
3. To know whether the motion is slow or fast

Let us assume that you started to school on a bicycle and your friend started in a bus at the same time from a place.
a) Who reaches the school first? Why?
b) Do you find any difference in the time taken by bicycle and bus to reach the school?
Answer:
a) My friend reached the school first. Because he started in a bus and I started on a bicycle.
b) Bus reaches the school fast. It means bus took less time to reach the school. Bicycle took more time to reach the school.

Question 10.
Observe following pairs of objects that are in motion. Compare their motions and decide which moves slower and which move faster. Mark (S) in relevant box.
a) Whether the motion of a body is slow or fast?
Answer:

a) The body is said to be moving fast if it takes less time to travel the given distance as compared to another body.

Question 11.
Do we need to know about distance covered, time taken by the body in motion to decide whether the motion is slow or fast?
Answer:
Yes, we need to know about distance covered, time taken by the body in motion, to decide whether the motion is slow or fast.

Question 12.
Priya, Karthik, Divya and Kiran participated in a 100 m. running race. They took 20 s, 22s, 25s and 28s respectively to reach the finishing line. Who do you think ran the fastest and whose running is slowest? Why?
Answer:

1. Obviously we can see that all of them ran the same distance of 100 m but time taken to cover the distance was different.
2. Priya took the shortest time of 20 seconds which shows that she was the fastest.
3. Kiran took the longest time of 28 seconds which shows that he was the lowest.

Question 13.
Write the units of time.
Answer:
The basic unit of time is a second(s). Larger units of time are minutes (min) and hours (h).
Table: Units of time

Question 14.
What is the need to know the speed? How do we know it?
Answer:

1. Many objects in the world around us are moving.
2. To compare how fast they are moving, we need to know their speed.
3. You may have observed the speedometer in motor cars which tells us how fast the car is travelling.
4. Usually, the speedometer in a vehicle shows the distance travelled in kilometers and the needle shows the speed of the journey in kilometers per hour.
5. Look at the speedometers of two vehicles shown here and decide which vehicle is slower.
   Car – 1 is slower.
   

Question 15.
How do you calculate the average speed of any object?
Answer:

1. Average speed = Total distance travelled / Total time taken to travel the distance.
2. Thus we can define speed of an object as the distance travelled by it in a unit of time.

Question 16.
What are the units of speed?
Answer:
Units of speed.

1. Depending on the need and context, speed is measured in different units.
2. Unit of speed in S.I. system is meter per second (m/s)
3. Another unit commonly used for speed is kilometer per hour (Km/h).
4. The basic unit of speed is m/s.

Question 17.
Observe motion of the car.

1. The distance between the driver and the car changes. ( )
2. The distance between the car and gate of the house is changed. ( )
3. There is no change in the position of gate of the house with respect to its surroundings. ( )
4. There is no change in the position of the car with respect to its surroundings. ( )

Answer:

1. The distance between the driver and the car does not change.
2. The distance between the car and gate of the house is changed. (Correct statement)
3. There is no change in the position of the gate of the house with respect to its sourroundings (Correct statement)
4. There is change in the position of the car with respect to its surroundings.

Question 18.
Show that 1 km/h = 5/18 m/s.
Answer:
1 km = 1000 m
and 1 h = 3600 s
1 km / h = 1000 m/3600 s = 5/18 m/s

Question 19.
Consider a car driven on a road. A person seated beside the driver recorded the distance travelled after every 10 minutes by noting the distance reading in the
speedometer. The distance travelled by the car at different instances of time is as follow.
a) What is the total distance travelled by the car?
b) What is the time taken to travel the distance?

c) How do you find the speed of the car?
d) Is the speed of the car uniform throughout the journey?
Answer:
a) Total distance travelled by the car = 60 km.
b) Time taken = 40 min.
c) To find the speed of the car in the journey we should calculate total distance travelled by the car and the total time taken to cover that distance.
Total distance travelled by the car = 60 km
Time taken = 40 min.
The distance must be either in meters or kilometers and time in seconds or hours. We express the speed either in m/s or in km/h. In this example distance is 60 km and time is 40 min.
1 hour = 60 min

Thus, the car travelled with an average speed of 90 km/h.
d) From the table, we notice that the car has covered unequal distances in equal intervals of time (10 min), which shows the speed of the car is not uniform.

Question 20.
The speed of a bus is 72 km/h, whereas the speed of a car is 12.5 m/s. Which vehicle moves faster?
Answer:
1) The speed of the bus is = 72 km/h
= 72 × \(\frac{5}{18}\) = 20 m/s
2) The speed of the car is = 12.5 m/s
3) As the speed of the bus is more than the speed of the car, the bus moves faster.
Note: To compare two speeds. They must be expressed in the same units. In the above example, speed of a bus is expressed in km/h and the speed of a car in m/s, tp compare these speeds, one of them must be converted to other.
Speed of a bus = 72 km/h = 20 m/s

Question 21.
How can you prove that motion is relative to the observer?
Answer:
Observing motion of the car.
Look at the pictures.

1. Imagine that you sat in the moving car beside the driver.
2. As the car moves, the distance between you and the landmarks like buildings, trees, poles etc., outside the car changes.
3. This change in the scene you view through the window indicates that the car is moving.
4. However your position with respect to the driver of the car remains the same.
5. That is you and the driver of the car are at rest with respect to each other, but both of you are in motion with respect to the surroundings outside the car.
6. A body may be at rest with respect to one set of surroundings and at the same time be in motion with respect to another set of the surroundings.
   Thus motion is relative to the observer.

Question 22.
Observe the following pictures. Read the statement below the first picture and write similar statements about other pictures.
a) 1) The man in the boat is moving in respect to the bank of river.

2) He is at rest with respect to the boat.

b) 1) The girl on the swing is with respect to the to seat of the swing.

A) The girl on the swing is at rest with respect to the seat of the swing.
2) She is with respect to the garden.
A) She is moving with respect to the garden.

c) 1) The girl on the bicycle is in respect to the road.

A) The girl on the bicycle is in motion in respect to the road.
2) She is in respect to the bicycle.
A) She is at rest in respect to the bicycle.

Question 23.
How are the hands of wall clock and the movement of a butterfly in a garden described?
Answer:

1. Imagine the movement of hands in a wall clock and the movement of a butterfly in a garden.
   
2. In these two cases hands of wall clock and the butterfly are in motion.
3. They change their positions with time.

Question 24.
a) What difference do you find in the movement of hands of clock and the body of butterfly?
b) In which case is the change of position with time constant?
Answer:
a)

1. We observe that in case of the wall clock, Change in position of minute hand is same for every minute.
2. How do we know this?
3. Measuring the angle between two positions of the minute hand is the way.

b) 1) But in the case of the butterfly, the change in its position is not constant while it is flying from one flower to another in the garden.

Question 25.
Observe the following tables, showing distances travelled by two different cars for different instances of time.

1) Which car has travelled equal distances in equal intervals of time?
2) Which car has travelled unequal distances in equal intervals of time?
Answer:

1. Obviously we notice that for car – A, the change in position in every 10 seconds is 150 m. But for car – B, the change in position is not constant.
2. For 1st 10 seconds, it is 50 m, for 2nd 10 seconds, it is 40 m, for 3rd 10 seconds it is 90 m, and for 4th 10 seconds it is 50 m.
3. Thus motion of car – A is uniform and motion of car – B is non – uniform.

Question 26.
Define uniform motion and non- uniform motion.
Answer:

1. Uniform motion : If a body covers equal distances in equal intervals of time, it is said to be in uniform motion.
2. Non – uniform motion : If a body covers unequal distances in equal intervals of time, it is said to be in non – uniform motion.

Question 27.
Observe the following motions of objects, State whether they are in rotatory motion? Draw a line showing axis of rotation by using pencil.
Answer:

Question 28.
Take a table tennis ball, and keep it on the surface of a table. Push the ball with your finger and observe its motion. Is it in Rotatory motion or in Translatory motion?
Answer:

1. When you push the ball on the surface of a table, it moves from one end to the other end and all the particles of the ball also move along the direction of motion of the ball.
   
2. Hence the balls is in translatory motion.
3. Similarly, each particle of the ball moves in a circular path about a particular line, when the ball rolls on the surface.
4. Therefore it is in rotatory motion.
5. Thus in the above example the ball possesses both translatory and rotatory motions.

Question 29.
Observe following motions of bodies and label them as Rotatory (R), Translatory(T), Translatory and Rotatory (TR).
Answer:

Question 30.
Take a cell phone. Go to ‘setting’ and open ‘stop clock’ option. If you are not able to do this take help from your friend or teacher. Measure the time taken for the events mentioned in the table.

Which event has taken more time to complete? Think! How much time does it take to sing the national anthem?
Answer:
The student is advised to do this activity in the school and fill up the columns.

Question 31.
Write the motion of different parts of a bicycle while it is in motion.
Answer:
a) The wheel: Rotatory and Translatory motion.
b) The cycle chain: Rotatory motion.
c) The pedal with its arm: Rotatory.
d) The movement of feet pedaling Rotatory.
e) The rider along with the bicycle; Translatory.

Question 32.
Identifying Uniform and Non – Uniform motion.
Identify uniform and non uniform motions among the following examples and mark Uniform as (U) and Non-Uniform as (NU).
Answer:
1. Movement of hands of a clock. ( U )
2. A boy cycling in a crowded place. ( NU )
3. Movement of a housefly. ( NU )
4. The fan in an air cooler running at fixed speed. ( U )
5. A train entering into a railway station,. ( NU )
6. Kite in the air ( NU )
7. Rotation of the earth. ( U )

Question 33.
Look at the following pictures.

The bus moved from point ‘A’ to ‘B’ in a certain interval of time.
Think and answer the following questions:
1. Do all the parts of bus (like wheels, head lights, windows etc., move along from point A’ to B’?
2. Is the direction of motion of bus along straight line or curved line?
Answer:

1. Yes all parts of bus (like wheels, head lights, windows … etc.,) move along from point A to B.
2. The direction of motion of bus is along straight line.
3. If all parts of a moving body move in the direction of motion then the motion is said to be translatory motion.

Question 34.
Observe the following table, and state the paths of motion for each case by putting (✓) mark in the relevant column.

Answer:

Question 35.
Identify oscillatory motion among the following and put (✓) mark in the brackets given.
Answer:
A spinning top (- )
Bullet from a gun (-)
Typewriter key (✓)
Motion of a potter’s wheel. (-)
Motion of a vibrating sitar string. (✓)
Motion of a car taking a turn while moving. (-)
Ringing of a bell (✓)
A bouncing belli (✓)

Question 36.
Observe the following pictures and answer the following questions.

1. What similarity do you find in the motions of the above given situations?
2. Are the objects in motion following the same path again and again?
3. Is the direction of motion constant?
4. What type of motion is this?
5. Define oscillatory motion.

Answer:

1. If we critically examine the above mentioned motions, we understand that in each case the objects move backwards and forwards or upward and downward, on the either side of a fixed point or a line.
2. Yes. For example, the girl on a swing moves backwards and forwards, on either side of the rest position of the swing.
3. Similarly in other cases also the body is in ‘to’ and ‘fro’ motion along the same path of motion.
4. This type of motion is called oscillatory motion.
5. Oscillatory motion: (Definition)
   The ‘to’ and ‘fro’ motion of an object about a fixed point always following the same path is called oscillatory motion.

Question 37.
How do you communicate the meaning of the terms ‘faster’ and ‘slower’ with the help of situation showing drawings?
Answer:
We understand that the distance travelled by an object in a given interval of time can help us to decide which one is faster and which one is slower.

1. We use the word time very often in our daily life. Look at the following examples.
2. If we observe the above examples, we use the word ‘time’ for different purposes.
3. In some situations, without using the word ‘time’, we express the duration of time like ‘so late’, so early’ etc.

Question 38.
How do we measure or estimate time? Explain with an example.
Answer:

1. Ravi and Sathish started for school at 8.00 a.m. from their houses which are side by side. Ravi started on a bicycle and Sathish by walk.
   • Who will reach the school first? How much earlier will he be compared to the other?
   • How do you measure ‘early’ or ‘late’ arrival at school?
     
2. You can easily estimate that Ravi reaches the school earlier than Sathish.
3. But to answer the question of how early Ravi reached, we need to measure the times taken by both Ravi and Sathish and find the difference of time between both the cases.
4. For this we need time measuring instruments like watches, clocks etc.
5. Nowadays, we use different instruments like electronic clocks, digital clocks, quartz clocks etc. to measure time.
6. A few decades ago people used pendulum clocks that have now become rare.

Question 39.
What are the different units for measuring time?
Answer:
Like minutes and hours, week, fortnight, month, season, ayanam are also units for measuring time.

Question 40.
How is the measurement of time done?
Answer:

1. Stop Clocks are used to measure time accurately.
2. We have seen stop clocks in the laboratory.
   
3. We use stop clocks in the laboratory to measure short intervals of time like time taken for completion of chemical reaction, time taken by the pendulum for one oscillation etc.
4. Nowadays we find stop clocks almost in all cell phones.
5. In our daily life stop clocks help measure pulse rate etc.
6. Apart from this, they also help us to accurately measure the times in running races, swimming races, etc.

Question 41.
Travel on a motor vehicle with your father to market or any other place and observe the changes in speedometer reading.
Note the exact time when you started from home and observe the speedometer reading carefully and note it and the corresponding time in the table. Some examples are given in the table.

a) Does the speed of the vehicle remain the same throughout the journey?
b) If not, what can you say about the speed of the vehicle during the journey?
Answer:

1. We experience in our everyday life that most of the objects in motion do not have the same speed throughout the journey.
2. To express the speed of the object, we consider its average speed.
   a) The speed of the vehicle is not the same throughout the journey.
   b) If such is the case, we consider its average speed.

Question 42.
We can classify motion based on the path taken by the bodies during motion. What are translatory motion and rotatory motion?
Answer:
Translatory motion: If all parts of a moving body move in the direction of motion, then the motion is said to be translatory motion.
Rotatory motion: Movement of any object about an axis.

Question 43.
i) How many types of motions are there and what are they?
ii) Read the table and identify the motion.
If the motion is Rotatory, put (R), Translatory (T), both Rotation and Translatory (RT), Oscillatory (O).

Answer:
a) There are 3 types of motions.
They are: 1) Translatory motion; 2) Rotatory motion and 3) Oscillatory motion.

b)

Question 43.
Why do you think the objects like trees, buildings, electric poles, etc. appear to be moving when you are sitting inside a moving bus or train?
Answer:

1. An object may be in the state of movement and at the state of rest at the same time.
2. It happens when the objects compared with different surroundings.

Question 44.
Write the motion of different parts of a bicycle while it is in motion.
i) The wheel
ii) The cycle chain
iii) The pedal with its arm
iv) The movement of the rider along with the bicycle
Answer:
1) The wheel – Rotatory motion
2) The cycle chain – Rotatory and transverse motion
3) The pedal with its arm – Rotatory motion
4) The movement of the rider along with the bicycle – Transverse motion

AP State Syllabus AP Board 7th Class Science Important Questions Chapter 10 Nutrition in Plants

AP State Syllabus 7th Class Science Important Questions 10th Lesson Nutrition in Plants

7th Class Science 10th Lesson Nutrition in Plants Important Questions and Answers

Question 1.
How is the process of photosynthesis carried on in plants?
Answer:

1. We know that plants take water through their roots and air though the stomata of their leaves. (There are some other parts like loose tissues and lenticels present on the bark of plant through which exchange of air takes place).
2. We also know that leaves contain the green substance, chlorophyll.
3. In the presence of sun light the process of photosynthesis takes place as follows. Green parts of plants use carbon dioxide in the presence of sunlight along with water to make glucose starch and other food materials.
   

Question 2.
What effect light has on the formation of starch in leaves? Describe an activity to find out.
Answer:

1. We need to find out if starch is present in leaves. We already know how to test for starch, but a problem arises if we try this test with leaves.
2. Leaves are green in colour. When iodine solution is put on a leaf, it should turn blue if starch is present.
3. However, the green colour of the leaf disguises the blue colour.
4. So we must first remove the green colour of the leaves if we want to test whether they contain starch.
5. The way to do this is to first put the leaves in a boiling tube and boil them in alcohol.
6. 4 to 5 leaves of a plant were plucked in the afternoon.
7. After removing their green colour in the way described above, they were put in diluted iodine solution.
8. The leaves turned black.
   
9. It means the leaves has starch in them.
10. In the second part of the experiment, 4 to 5 leaves of the same plant were covered with black paper without removing them from the plant.
11. The way the black paper was cut and fixed to the leaves is shown in the figure.
12. These leaves were plucked two days later. Their green colour was removed and they were dipped in iodine solution.
13. The leaves turned black in the pattern shown in the figure.
14. We will notice with the iodine solution test that starch was not present in the portion of the leaves covered with black paper.
15. This experiment confirms that light is essential for the formation of startch in plants.

Question 3.
Do plants produce only starch? If not, what are the other compounds it could produce? explain.
Answer:

1. We know that starch, fats and proteins are present in food.
2. They are also present in plants.
3. Plants produce sugar first, which is converted to starch and then another compound as well.
4. But plants need other nutrient elements to do this.

Question 4.
What are the main nutrients for plants ? What do you mean by micronutrients?
Answer:

1. The main nutrients needed are nitrogen, potassium and phosphorus.
2. Plants require many other nutrient elements as well, but these are needed only in minute quantities.
3. Hence, they are called micronutrients.
4. Plants absorb these nutrient elements from the soil through their roots.

Question 5.
What is Cuscuta? Explain what is meant by hetero trophic nutrition.
Answer:

1. We see yellow thread-like structures twining around the stem, branches and leaves of some trees.
2. Figure shows such a plant.
3. This thread-like plant is Cuscuta. It neither has leaves nor Chlorophyll.
4. Cuscuta takes food from the plant on which it is climbing.
   
5. Like humans and animals such plants depend on the food produced by other plants.
6. This mode of nutrition is called heterotrophic nutrition.

Question 6.
What are saprophytes? Where do they grow?
Answer:

1. Often after rains we find umbrella like structures growing from the ground.
2. Such plants are called saprophytes.
3. They grow on dead / decaying matter.
4. Mushrooms belong to this type of plants.

Question 7.
What is fungi? Where do you find it?
Answer:

1. Black and white spots appearing on bread pieces, pickles, when kept in moist places. These spots develop due to the growth of fungi, which is a type of plant.
2. All these types of plants do not contain chlorophyll so they simply absorb organic material usually from decaying matter.

Question 8.
Write a brief note on ‘insectivorous plants’.
Answer:

1. A few plants manufacture their own food but also obtain a part of their nutrition from insects.
2. Leaves of these plants are specially modified to trap insects.
   
3. These plants grow in areas deficient in nitrogen.
4. Hence they meet their nitrogen requirements from insects.
5. Being green in colour, they can manufacture their own food.
6. Droseras, Utricularia, Venusflytrap are examples of some such insectivorous plants.
7. These are also called as carnivorous plants.

Question 9.
Mention some plants on whose roots bacteria grow.
Answer:
Some plants like those of the Dal family have a type of bacteria growing on their roots in nodules. The bacteria fixes nitrogen for the plant while it gets shelter in the roots of these plants. Such an association is beneficial to both groups and called symbiosis.

Question 10.
What are Lichens? Write a note about it.
Answer:
There are colonies of algae and fungi living together in a symbiotic relationship. These colonies are known as Lichens. This relationship starts with the attack of the algal colony by a type of fungus. It is an example of balanced parasitism then. Later as algae survive, they are given protection from intense light and conditions of drying up due to the presence of fungus colony. The fungus gets food from its partner.

Question 11.
Describe the experiment conducted by Jan Baptista Von Helmont and discuss his results.
Answer:

1. In the year 1648 a Belgian scientist Jan Baptista Von Helmont conducted an experiment that continued for five years.
   
2. He took a small willow tree and planted it in a large pot of soil.
3. Before he did this he carefully measured the mass of the dry soil and the mass of the tree.
4. He covered the soil with a lid so that nothing could fall onto the surface of the soil and add to its mass.
5. There were holes in the lid so that the tree could grow out of the soil and so that air and water could reach the roots. Von Helmont left the tree for five years, giving it only rain water to drink.
   
6. At the end of the five years he measured the mass of the tree and the mass of the dry soil for a second time.
7. The results of this experiment are shown below.
8. This experiment changed the belief of hundreds of years. This was because Von Helmont arrived at a result that –
9. 
   a) The substances needed for the growth of a plant do not come from the soil only.
   b) The plant grow because of the water it gets.

Question 12.
Who was the first to point out a possible role of light in plant nutrition?
Answer:

1. People tried to check the conclusions of Von Helmont and thus experiment after experiment followed.
   
2. Stephan Hales described the leaves as organs of transpiration (loss of excess water from plant body) and he said that plants exchange gases with their surrounding air.
3. Furthermore, he was the first to point out a possible role of light in plant nutrition.

Question 13.
List the four major things needed by plants to carry out the process of photosynthesis.

Answer:

1. In nature, the presence of the green substance in leaves is essential for photosynthesis to take place.
2. This green substance is called chlorophyll. Plants get water from the soil through their roots while the process of photosynthesis takes place in the leaves.
   

Question 14.
Why is it necessary to irrigate the fields after sprinkling urea?
Answer:

1. Farmers sprinkle urea in rice or wheat fields whenever the leaves turn yellow.
2. The leaves soon become green again.
3. After sprinkling urea, farmers irrigate their fields.
4. Urea dissolves in water and stay near the roots of the rice plants.
5. The plants absorb this urea dissolved in water through their roots.
6. This is the reason why farmers irrigate the fields after sprinkling urea.
7. The rice or wheat plants get water and other nutrients dissolved in it thus.

Question 15.
How does the exchange of air take place in plants?
Answer:

1. Plants get water from the soil through their roots.
   They use carbon dioxide of air. This job is done by the leaves.
2. The leaves have tiny holes through which the exchange of air takes place.
   
3. These holes are so minute we can only see them with the help of a microscope.
4. They are called stomata.
5. It is through the stomata that the exchange of air in leaves takes place continuously.

Question 16.
Draw a diagram of mango tree and write its soliloquy.
Answer:

Question 17.
How do parasitic plants get food from the host plants?
Answer:
Parasitic plants develop special roots called haustoria, which penetrate into the tissues * of the host plant and absorb food materials from them.

Question 18.
What is herberium? How is it useful to us?
Answer:

1. Preservation of plant parts like leaves, flowers or whole plant is a traditional designery art.
2. If the plants are not available in a particular place then the plant physiologists collect those plants where they available and make them in the preservative form.
3. This is commonly known as herberium.
4. They study those plants, and these preserved plants also helpful for the future studies.

Question 19.
Read the para and answer the quesions given below.
Cascuta is a parasitic plant. This receives nutrients from the host plant. It has a finger like structure called haustoria. It inserts it into the stem of the host and receives nutrients.

1. Why do we call Cascuta a parasitic plant?
2. What helps to receive nutrients in Cascuta?
3. Why does Cascuta depend on host for nutrition?
4. Give some more examples of parasitic plants.

Answer:

1. Because Cascuta depends on other plants for food.
2. Haustoria.
3. As Cascuta has no chloroplasts to perform photosynthesis, it depends on other plants for food.
4. a) Corpse flower (Rafflesia plant)
   b) Hydnora plant
   c) Thurber’s stem sucker.

Question 20.
What happens if the stomata is absent in the plants?
Answer:

1. If there are no stomata in plant, transpiration will not occur.
2. Moreover, the gaseous exchange (CO₂, O₂) will not take place in plants.
3. Photosynthesis will not occur in plants.

Question 21.
In human beings respiratory organs are lungs. What are the respiratory organs of plants?
Answer:
Stomata act as respiratory organs in plants.

SCERT AP 7th Class Science Study Material Pdf 5th Lesson చలనం – కాలం Textbook Questions and Answers.

AP State Syllabus 7th Class Science 5th Lesson Questions and Answers చలనం – కాలం

7th Class Science 5th Lesson చలనం – కాలం Textbook Questions and Answers

Improve Your Learning (అభ్యసనాన్ని మెరుగుపరచుకుందాం)

I. ఖాళీలను పూరింపుము.

1. వడి యొక్క ప్రమాణాలు (మీ/సె)
2. ఒక వస్తువు సమాన దూరాన్ని సమాన కాల వ్యవధిలో ప్రయాణిస్తే, దానిని ……. చలనం అంటారు. (సమ)
3. 60 నిమిషాలు = ………….. సెకనులు. (8,600)
4. సగటు వడి = ప్రయాణించిన మొత్తం దూరం / ……………. (ప్రయాణించిన కాలం)
5. ISRO అంటే ………. (భారత అంతరిక్ష పరిశోధనా కేంద్రము)
6. జియో స్టేషనరీ ఉపగ్రహాలు ………… కొరకు ఉపయోగిస్తారు. (సమాచార ప్రసరణ)

II. సరైన జవాబు సూచించు అక్షరమును బ్రాకెట్ లో రాయండి.

1. వడి, దూరం మరియు కాలం మధ్య సరైన సంబంధం
A) వడి = దూరం/కాలం
B) వడి = కాలం/దూరం
C) కాలం = వడి/దూరం
D) దూరం = వడి/కాలం
జవాబు:
A) వడి = దూరం/కాలం

2. కింది వాటిలో సాధారణ విషయం ఏమిటి?
ఎగిరే హెలికాప్టర్ యొక్క ప్రొపెల్లర్ కదలిక, గడియారం యొక్క నిమిషాల ముల్లు, జెయింట్ వీల్ చలనం.
A) అన్నీ స్థానాంతర చలనానికి ఉదాహరణలు
B) అన్నీ డోలన చలనానికి ఉదాహరణలు
C) అన్నీ భ్రమణ చలనానికి ఉదాహరణలు
D) A మరియు C
జవాబు:
C) అన్నీ భ్రమణ చలనానికి ఉదాహరణలు

3. కింది వాటిలో ఏది డోలన చలనం కాదు?
A) విద్యుత్ గంటలో సుత్తి చలనం
B) పరుగెత్తుతున్నప్పుడు మీ చేతుల చలనం
C) తూగుటూయల మీద పిల్లల చలనం
D) బండి లాగునప్పుడు గుర్రం యొక్క చలనం
జవాబు:
D) బండి లాగునప్పుడు గుర్రం యొక్క చలనం

4. కిందివాటిలో ఏది సరైనది కాదు?
A) సమయం యొక్క ప్రాథమిక ప్రమాణం సెకన్
B) ప్రతి వస్తువు యొక్క చలనం సమచలనం.
C) 1 కి.మీ/గం = 5/18 మీ/సె.
D) వేగమును కి.మీ/గం. లలో వ్యక్తపరుస్తారు.
జవాబు:
C) 1 కి.మీ/గం = 5/18 మీ/సె.

III. జతపరచండి.

జవాబు:

IV. ఈ క్రింది ప్రశ్నలకు జవాబులు రాయండి.

ప్రశ్న 1.
రెండు స్టేషన్ల మధ్య దూరం 240 కిమీ. ఈ దూరాన్ని పూర్తి చేయడానికి ఒక రైలుకు 4 గంటలు పడుతుంది.
రైలు వేగాన్ని మీటర్/సెకనులలో లెక్కించండి.
జవాబు:

ప్రశ్న 2.
ఒక వస్తువు ఒకే సమయంలో స్థానాంతర మరియు భ్రమణ చలనాలను కలిగి ఉంటుందా? ఒక ఉదాహరణ ఇవ్వండి.
జవాబు:

1. ఒక వస్తువు ఒకే సమయంలో స్థానాంతర మరియు భ్రమణ చలనాలను కల్గి ఉంటుంది.
2. దొర్లుతున్న బంతి గాని కదులుతున్న సైకిల్ కాని వాటి స్థానం నుండి ముందుకు కదులుతూ స్థానాంతర చలనాన్ని చూపుతాయి.
3. అదే సమయంలో ఆ వస్తువులు గుండ్రంగా తిరుగుతూ భ్రమణ చలనం ప్రదర్శిస్తాయి.

ప్రశ్న 3.
టైలర్లు ఉపయోగించే కుట్టు యంత్రంలో, అది నడుస్తున్నప్పుడు కుట్టు యంత్రాల భాగాల చలన రకాన్ని పేర్కొనండి.
ఎ) చక్రం
బి) సూది
సి) వస్త్రం
జవాబు:
ఎ) చక్రం – భ్రమణ చలనం
బి) సూది – డోలన చలనం
సి) వస్త్రం – స్థానాంతర చలనం

ప్రశ్న 4.
సైకిల్ చలనంలో ఉన్నప్పుడు దాని వివిధ భాగాల చలనాలను తెలియజేయండి.
ఎ) చక్రం
బి) సైకిల్ చైన్
సి)పెడల్ చలనం
డి) సైకిల్ తో పాటు నడిపే వ్యక్తి చలనం
జవాబు:
సైకిల్ చలనంలో ఉన్నప్పుడు వివిధ భాగాలు వేరు వేరు చలనాలను చూపుతాయి.
ఎ) చక్రం – భ్రమణ చలనం
బి) సైకిల్ చైన్ – దీర్ఘవృత్తాకార చలనం
సి) పెడల్ – వృత్తాకార చలనం
డి) సైకిల్ నడిపే వ్యక్తి – స్థానాంతర చలనం

ప్రశ్న 5.
జాన్ ఒక రాయికి తీగను కట్టి దానిని గిరగిర తిప్పాడు. అక్కడ మీరు ఏ రకమైన చలనాన్ని పరిశీలిస్తారు?
జవాబు:
రాయికి తీగను కట్టి గిరగిరా తిప్పినపుడు అది వృత్తాకార మార్గంలో భ్రమణ చలనాన్ని ప్రదర్శిస్తుంది.

ప్రశ్న 6.
సమచలనం మరియు అసమచలనము అంటే ఏమిటి? ప్రతి చలనానికి నాలుగు ఉదాహరణలు ఇవ్వండి.
జవాబు:
సమచలనం :
ఒక వస్తువు సమాన కాలవ్యవధులలో సమాన దూరాలు ప్రయాణించినట్లయితే, దానిని సమచలనం అంటారు.
ఉదా :

1. గడియారంలో ముళ్ళు చలనం
2. తిరుగుతున్న ఫ్యాన్
3. ఒకే వేగంతో వెళుతున్న రైలు
4. ఒకే వేగంతో వెళుతున్న కారు

అసమచలనం :
ఒక వస్తువు సమాన కాలవ్యవధులలో అసమాన దూరాలు ప్రయాణించినట్లయితే దానిని అసమ చలనం అంటారు.
ఉదా :

1. సీతాకోక చిలుక ప్రయాణం
2. ట్రాఫిక్ లో కదులుతున్న కారు
3. స్టేషన్ లోకి వస్తున్న రైలు
4. ఎత్తు నుండి దొర్లుతున్న రాయి

ప్రశ్న 7.
రాకెట్ యొక్క చలనం వేగవంతమైన చలనం అని మీ స్నేహితుడు మీకు చెప్పారు. మీరు అంగీకరిస్తారా? వస్తువు యొక్క చలనం నెమ్మదిగా ఉందా లేదా వేగంగా ఉందా అని మీరు ఎలా నిర్ణయిస్తారు?
జవాబు:

1. రాకెట్ చాలా వేగంతో ప్రయాణిస్తుంది. దాని వేగం సెకను సుమారు 12 కి.మీ. ఉంటుంది. ఇది అద్భుతమైన వేగం.
2. ఒక వస్తువు యొక్క చలనము నెమ్మదిగా ఉందో వేగంగా ఉందో నిర్ణయించటానికి అది ప్రయాణించిన దూరం, అందుకు పట్టిన సమయం ఆధారంగా నిర్ణయించవచ్చు.
3. ఒక వస్తువు ఏకాంక కాలంలో ప్రయాణించిన దూరాన్ని దాని వడిగా పిలుస్తారు.
4. వడి = ప్రయాణించిన మొత్తం దూరం / ప్రయాణించిన కాలం.
5. దీనికి ప్రమాణాలు మీటర్/ సెకన్ లేదా కిలోమీటరు / గంట.
6. 1 కిలోమీటరు / గంట = 5/18 మీటర్/ సెకన్.
7. వస్తువు యొక్క వడి ఆధారంగా అది వేగంగా ప్రయాణిస్తుందా లేదా నెమ్మదిగా ప్రయాణిస్తుందా అని నిర్ధారించవచ్చు.
8. వస్తువు యొక్క వేగాన్ని సూచించటానికి వాహనాలలో స్పీడో మీటరు ఉంటుంది.

ప్రశ్న 8.
కాలాన్ని కొలవడంలో లేదా అంచనా వేయడంలో గడియారాలు మరియు వాచను మీరు ఏవిధంగా అభినందిస్తారు?
జవాబు:
కాలం ఒక అద్భుతం
దాన్ని కొలవగలగటం మహా అదృష్టం
అందుకు ఉందిగా గడియారం
తెలుపుతుంది నీకది సమయం
చేయకు నీవు కాలాన్ని దుబారా
విలువ తెలిసిన జీవితం అమూల్యం

7th Class Science 5th Lesson చలనం – కాలం InText Questions and Answers

7th Class Science Textbook Page No. 137

ప్రశ్న 1.
అన్ని వస్తువుల కదలికలు ఒకే విధమైనవా?
జవాబు:
కాదు. వస్తువుల చలనం ప్రధానంగా మూడు రకాలుగా ఉంటుంది.

ప్రశ్న 2.
వస్తువులు కదిలేలా, కదిలే వస్తువు విరామస్థితికి వచ్చేలా చేసేది ఏమిటి?
జవాబు:
బలం వస్తువులను కదిలేలా, కదిలే వస్తువు విరామ స్థితికి వచ్చేలా చేస్తుంది.

ప్రశ్న 3.
రైలు సరళరేఖ వెంబడి కదిలితే ఆ చలనాన్ని ఏమంటారు?
జవాబు:
రైలు సరళరేఖ వెంబడి కదిలితే ఆ చలనాన్ని స్థానాంతర చలనం అంటారు.

ప్రశ్న 4.
పక్షులు చలించే దిశ, వాటి రెక్కల కదలిక ఒకే విధంగా ఉంటుందా?
జవాబు:
లేదు. పక్షులు ముందుకు కదులుతూ స్థానాంతర చలనం చూపితే, వాటి రెక్కలు పైకి క్రిందకు కదులుతూ కంపన చలనం చూపుతాయి.

7th Class Science Textbook Page No. 149

ప్రశ్న 5.
ఒక వస్తువు ఏక కాలంలో స్థానాంతర మరియు భ్రమణ చలనం రెండింటిని కల్గి ఉంటుందా? వివరించండి.
జవాబు:
సైకిల్ ఒక సరళరేఖలో కదులుతున్నప్పుడు దాని చక్రం చలనాన్ని పరిశీలించండి.

సరళరేఖా మార్గంలో కదులుతున్న సైకిల్ టైర్ యొక్క చలనాన్ని మీరు పరిశీలిస్తే ఆ టైర్ లోని అన్ని భాగాలు ఒకే మార్గంలో కదులుతున్నాయి. అందువల్ల అది స్థానాంతర చలనంలో ఉందని చెప్పవచ్చు.

గుండ్రంగా తిరుగుతున్న సైకిల్ టైరును మీరు గమనిస్తే అది దాని అక్షం పరంగా వక్రమార్గంలో (వృత్తాకారం) కదులుతుంది. కాబట్టి సైకిల్ టైరు భ్రమణ చలనంలో ఉందని చెప్పవచ్చు.

సరళరేఖా మార్గంలో ప్రయాణిస్తున్న సైకిల్ టైరు స్థానాంతర చలనము మరియు భ్రమణ చలనాన్ని కలిగి ఉంటుంది.

7th Class Science Textbook Page No. 153

ప్రశ్న 6.
సగటు వడిని ఎలా లెక్కిస్తారు?
జవాబు:
సగటు వడి వస్తువు ప్రయాణించిన మొత్తం దూరం మరియు పట్టిన కాలముల నిష్పత్తితో లెక్కిస్తారు.

7th Class Science Textbook Page No. 155

ప్రశ్న 7.
ఏ భారతీయ సంస్థ రాకెట్ కొరకు పని చేస్తుంది?
జవాబు:
ISRO సంస్థ భారతదేశంలో రాకెట్ల కొరకు పనిచేస్తుంది.

7th Class Science Textbook Page No. 159

ప్రశ్న 8.
వాతావరణ నివేదికలు ఎలా తయారుచేయగల్గుతున్నారు?
జవాబు:

1. కృత్రిమ ఉపగ్రహాల ద్వారా శాస్త్రవేత్తలు భూవాతావరణాన్ని అధ్యయనం చేస్తారు.
2. ఉపగ్రహాలు అందించే ఈ సమాచారాన్ని విశ్లేషించి ఒక ప్రాంత వాతావరణాన్ని, వర్షపాతాన్ని, తేమను అంచనా వేయగలరు.
3. వీటితోపాటు తుపానుల రాక, వాటి గమనాన్ని నిశితంగా పరిశీలించగలరు.

ప్రశ్న 9.
గూగుల్ మ్యాప్స్ మార్గాలను ఎలా ఇవ్వగల్గుతున్నాయి?
జవాబు:

1. గూగుల్ మ్యాప్స్ అనేవి, మార్గాలను చూపించే అంతర్జాల వేదికలు.
2. ఇవి శాటిలైట్ అందించే చిత్రాలను మన స్థానాలను మ్యాపింగ్ చేసి కృత్రిమ మేథ ద్వారా మార్గాలను చూపుతాయి.

ప్రాజెక్ట్ పనులు

7th Class Science Textbook Page No. 163

ప్రశ్న 1.
ఒక టెన్నిస్ బంతి లేక క్రికెట్ బంతిని స్థానాంతర, భ్రమణ మరియు డోలన చలనాలు చేయించండి. దానిపై ఒక నోట్స్ వ్రాసి మీ స్నేహితులతో చర్చించండి.
జవాబు:

1. ఒక క్రికెట్ బంతిని తీసుకొని దూరంగా ఉన్న మా స్నేహితునికి క్యాచ్ విసిరేసాను – ఇది స్థానాంతర చలనాన్ని సూచిస్తుంది.
2. అదే బంతిని గుండ్రంగా తిప్పుతూ చేతి వ్రేళ్ళపై నిలబెట్టటానికి ప్రయత్నించాను – ఇది భ్రమణ చలనాన్ని సూచిస్తుంది.
3. క్రికెట్ బంతిని నేలపై దొర్లే విధంగా మిత్రుని వైపుకి విసిరాను. ఇది భ్రమణ మరియు స్థానాంతర చలనాలను చూపుతుంది.
4. బంతిని ఒక త్రాడుకు కట్టి అటూ ఇటూ ఊపాను. ఇది డోలన చలనాన్ని సూచిస్తుంది.

ప్రశ్న 2.
నీటి గడియారం లేదా ఇసుక గడియారం తయారు చేసి, కాలాన్ని తెలుసుకోవడానికి దాన్ని ఉపయోగించండి.
జవాబు:

1. రెండు గాజు సీసాలను తీసుకొని వాటి మూతలకు సన్నని రంధ్రము చేశాను.
2. సన్నని ఇసుకను తీసుకొని ఒక బాటిల్ లో పోసాను.
3. రెండు బాటిలకు మూతలు పెట్టి వాటి రంధ్రాలు కలిసే విధంగా అతికించాను.
4. ఇప్పుడు ఇసుక ఉన్న బాటిలను పైకి తిప్పి బోర్లించినపుడు సన్నని రంధ్రం ద్వారా ఇసుక క్రింది బాటిల్ లోనికి చేరటం ప్రారంభించింది.
5. మొత్తం ఇసుక పై నుండి కిందకు కారటానికి పట్టే సమయం కొలిచాను.
6. బాటిల్ ఇసుకను చేర్చటం లేదా కొంత తొలగించటం ద్వారా నిర్దిష్ట కాలాన్ని కొలిచే ఇసుక గడియారం తయారుచేయవచ్చు.

కృత్యాలు

కృత్యం – 1

ప్రశ్న 1.
కొన్ని వస్తువులను చలనము మరియు విరామస్థితి ఆధారంగా వర్గీకరించే ఒక కృత్యమును చేద్దాం.

జవాబు:

కృత్యం – 2

ప్రశ్న 2.
ఒక ఫుట్ బాల్ తీసుకోండి, మీ స్నేహితులతో మీ స్కూలు గ్రౌండకు వెళ్లండి. పటంలో చూపించిన విధంగా త్రిభుజాకారంలో నిలబడండి. బంతిని మీ దిశలో తన్నమని మీ స్నేహితుడిని అడగండి. మీరు బంతిని మరో స్నేహితుడి వైపుకు అందించడానికి ప్రయత్నించండి. ఆ బంతిని ఆపమని అతడికి చెప్పండి. ఇప్పుడు కింది ప్రశ్నలకు సమాధానం ఇవ్వండి.

మీ స్నేహితుడు బంతిని కదిలించటానికి దానిపై ఏం ప్రయోగించాడు?
జవాబు:
బలం
ఆ బంతి దిశను మార్చటానికి నీవు దానిపై ఏం ప్రయోగించావు?
జవాబు:
బలం

మీ స్నేహితుడు కదులుతున్న ఐంతిని ఆపడానికి దానిపై ఏం ప్రయోగించాడు ?
జవాబు:
బలం.

బలాన్ని ఎలా నిర్వచించవచ్చు?
జవాబు:
వస్తువు గమన స్థితి నుండి. నిశ్చల స్థితికి, నిశ్చల స్థితి నుండి గమన స్థితికి, దాని దిశను మార్చటానికి తోడ్పడునది బలం.

కృత్యం – 3

ప్రశ్న 3.
దూరం మరియు గమ్యస్థానంను వివరించడానికి ఏదైనా కృత్యంను నిర్వహించండి.
జవాబు:
మీ స్కూలులో మధ్యాహ్న భోజనమును వడ్డించే స్థలానికి, మీ బెంచ్ కి మధ్య దూరాన్ని లెక్కించడానికి ప్రయత్నించండి. దాని విలువ ఎంత?

మీ గమ్యస్థానం యొక్క దూరం మరియు దిశను తెలుసుకోవడానికి మీరు ఎప్పుడైనా గూగుల్ మ్యాపన్ను ఉపయోగించారా ?

ఇప్పుడు గూగుల్ మ్యాప్స్ ఉపయోగించి మీ స్వస్థలం నుంచి జిల్లా కేంద్రానికి మధ్య దూరాన్ని తెలుసుకోండి. దాని విలువ ఎంత?
జవాబు:
……………. కి.మీ. (సూచన : విద్యార్థి ఈ కృత్యంను స్వయంగా నిర్వహించాలి)

చిత్రాన్ని పరిశీలించండి. కవిత తన స్కూలుకు రెండు విధాలుగా చేరుకోవచ్చు. A, B రోడ్లలో ఏ మార్గం ద్వారా ఆమె స్కూలుకు త్వరగా చేరుకోవడానికి ఏ మార్గాన్ని మీరు సూచిస్తారు?’ మీరు తక్కువ దూరం కలిగిన మార్గమైన రోడ్డు Aను సూచిస్తారు కదా.

పై కృత్యం, ఉదాహరణల ద్వారా ఒక వస్తువు ఒక ప్రదేశం నుంచి మరో ప్రదేశానికి ప్రయాణించినప్పుడు, ఆ మార్గం పొడవును కొలవవచ్చు. అది ఆ రెండు స్థానాల మధ్య గల దూరం అవుతుంది. ఒక ప్రదేశం నుంచి మరో ప్రదేశానికి వస్తువు సరళరేఖా మార్గంలో ప్రయాణించినప్పుడు, అది త్వరగా చేరుకుంటుంది. సరళరేఖ మార్గం , యొక్క పొడవు రెండు ప్రదేశాల మధ్య గల అతి తక్కువ దూరం. దీనిని స్థానభ్రంశం అంటారు.

కృత్యం – 4

ప్రశ్న 4.
మీ ఫిజికల్ ఎడ్యుకేషన్ టీచర్ సహాయంతో 100 మీటర్ల పరుగు పందెం నిర్వహించండి. ప్రతి విద్యార్థి పరుగుపందెం పూర్తి చేయడానికి పట్టే సమయాన్ని లెక్కించడం కొరకు మొబైల్ ఫోన్ లో స్టాప్ వాచ్ ను లేదా ప్రయోగశాలలోని స్టాప్ వాచ్ ను ఉపయోగించండి. కింద ఇవ్వబడిన పట్టికను నింపండి.

జవాబు:

కృత్యం – 5

ప్రశ్న 5.
రాబర్ట్ మరియు కమల వారి పాఠశాలకి వచ్చేటప్పుడు వారు ప్రయాణించిన దూరం, అందుకు పట్టిన సమయము లెక్కించారు. ఆ దత్తాంశము ఈ క్రింద పట్టికలో చూపబడినది.
జవాబు:

కింద చూపిన దశలను అనుసరించి మీరు అను గీయవచ్చు:

1. రెండు అక్షాలను సూచించడానికి రెండు లంబ రేఖలను గీయండి. వాటిని OX, OYగా గుర్తించండి. OXను కాలం అక్షంగాను, OYను దూరం అక్షంగాను గుర్తించండి.
2. గ్రాఫ్ పేపర్ మీద దూరాన్ని మరియు కాలాన్ని సూచించడానికి స్కేల్‌ను ఎంచుకోండి.
   కాలం : 1 నిమిషం = 1 సెం. మీ.
   దూరం : 100 మీ. = 1 సెం. మీ.
3. మీరు ఎంచుకున్న స్కేల్ ప్రకారం సంబంధిత అక్షాలపై దూరం, కాలం విలువలను గుర్తించండి.
4. ప్రతి జత విలువను సూచించడానికి బిందువులను గుర్తించి, వాటిని కలపండి. ఇది ఇవ్వబడిన చలనానికి దూరం – కాలం ను సూచిస్తుంది.
5. దూరం – కాలం గ్రాఫ్ సరళరేఖ అయితే, వస్తువు స్థిరమైన వడితో కదులుతున్నట్లు సూచిస్తుంది. వస్తువు, యొక్క వడి మారుతూ ఉంటే, గ్రాఫ్ సరళ రేఖ కాకుండా ఏదైనా ఇతర ఆకారంలో ఉంటుంది.
6. దూరం కాలం గ్రాఫ్ నుండి ఏ సమయంలోనైనా వస్తువు ప్రయాణించిన దూరాన్ని మనం కనుగొనవచ్చు.