Mahesh

These AP 7th Class Science Important Questions 10th Lesson Changes Around Us will help students prepare well for the exams.

AP Board 7th Class Science 10th Lesson Important Questions and Answers Changes Around Us

Question 1.
What is a natural change?
Answer:
The change that is brought about by nature itself is called a natural change.

Question 2.
What are man made changes? Give two examples.
Answer:

1. Changes which are taken place by the involvement of human beings are called man made changes.
2. Examples for man made changes are cooking of rice, construction of buildings, preparation of laddu.

Question 3.
What are fast changes? Give examples.
Answer:

1. Changes which occur in short duration of time are called fast changes.
2. Burning of paper, cutting of piece of cake, firing of crackers, spinning of a top are the examples of fast changes.

Question 4.
What are the slow changes? Give examples.
Answer:

1. Changes which take longer duration of time to happen are called slow changes.
2. Examples for slow changes are growing of plant from seed to a tree, developmental changes in the child, rusting of iron, changes of season, formation of mountain etc.

Question 5.
What are reversible changes? Give examples.
Answer:

1. The changes in which the formed substance can be converted into their original substance are called reversible changes.
2. Example for reversible changes are melting of wax, magnetizing a needle using bar magnet etc.

Question 6.
What are irreversible changes? Give examples.
Answer:

1. Changes in which we cannot get the original substance by reversing the experimental conditions are called irreversible changes.
2. Examples are burning of wood, burning of diwali crackers, ripening of fruits, rusting of iron etc.

Question 7.
What are periodic changes? Give examples.
Answer:

1. The changes which are repeating at regular intervals of time are called as periodic changes.
2. Formation of the full moon and new moon, occurrence of seasons in every year at regular intervals, the heart beats of human beings are examples for periodic changes.

Question 8.
What are non-periodic changes? Give examples.
Answer:

1. Changes which do not occur at regular intervals of time and which can not be predicted are called non-periodic changes.
2. Examples are pattern of rainfall, storms in seas, volcanic erruptions etc.

Question 9.
“In a physical change, the chemical properties of a substance do not change.” Do you agree with this statement? How?
Answer:

1. Yes, I agree with this statement.
2. Why because, when a piece of gold is melted, it’s chemical composition remains the same in the solid form and also in the liquid form.

Question 10.
“A physical change is usually temporary and reversible in nature” – Do you agree with this statement? State the reason.
Answer:

1. I absolutely agree with this statement.
2. It is because, when water is heated, water vapours are formed. Once water vapours are cooled water can be obtained again.

Question 11.
“In a physical change, change in physical properties such as colour, shape and size of a substance may under go a change”. Do you support this statement? Why?
Answer:

1. I support this statement.
2. In cutting of vegetables changing physical properties, such as colour, shape and size of a substance.

Question 12.
What is galvanization?
Answer:
The process of deposition of a layer of zinc on iron is called “Galvanization.”

Question 13.
What is a chemical change? Give one example.
Answer:

1. Changes that occur with the formation of new substance with different chemical composition or transformation of a substance into another substance with the evolution or absorption of heat or light energy are called as chemical changes.
2. Example when Magnesium burns in the presence of oxygen, it forms magnesium oxide in the form of powdered ash.
   Magnesium + oxygen → Magnesium oxide

Question 14.
What is rusting?
Answer:

1. When ron reacts with atmospheric oxygen and moisture it forms a new substance called Iron oxide as rust on iron articles made of iron.
2. This process is known as rusting.
   Iron + oxygen (from air) + water → rust (iron oxide)

Question 15.
What are the reasons for global warming?
Answer:

1. Global warming is due to drastic increase in the emission of carbondioxide by the burning of fossil fuels.
2. Deforestation.

Question 16.
What are the reasons for acid rains?
Answer:

1. When coal and oils are burnt, they release acidic gases like NO₂ and SO₂.
2. They mix up with the water vapour and come down as acid rains.

Question 17.
The changes like chicks came out of eggs, blossoming flowers etc. are very pretty to see. List out such changes around you feel happy on observation.
Answer:

1. Swarming of honeybees
2. Rainbow formation
3. Clouds passing across the mountains.
4. Rows of birds flying in the sky.

Question 18.
Give examples for metals that do not rust.
Answer:

1. Metals like gold, silver, zinc do not rust even though they are exposed to moist air.
2. Zinc is used in Galvanization process to prevent rusting of iron articles.

Question 19.
How can you say that rusting is a chemical change?
Answer:

1. When the metals are exposed to air, they form metal oxides.
2. Hence, as new substances are formed, rusting is a chemical change.

Question 20.
Observe the following changes and decode weather they are physical or chemical changes? Mention the reason, a) Preparation of tea b) Making dough for roti.
Answer:
a) This is a chemical change. Water + Milk + Tea powder + Sugar → Tea Here tea is a new substance. Hence it is a chemical change,

b) Making dough for roti is a physical change as there is no formation of new substance.

Question 21.
How is an iron gate prevented from rusting?
Answer:

1. Iron gate when exposed to moisture and air gets rusted.
2. To prevent rusting of Iron gates it should be painted with a paint.

7th Class Science 10th Lesson Changes Around Us Short Questions and Answers

Question 1.
What are the examples for natural changes?
Answer:

1. Formation of day and night
2. Changes of weather.
3. Developmental changes of a child into an adult. ‘
4. rowth of a seed into a plant.

Question 2.
How can we prevent browning of cut fruits and vegetables?
Answer:

1. By keeping the cut vegetables in cold water, we can prevent browning of them.
2. Cold water prevents the outer surface of the potato and brinjal from colouring.
3. Small quantities of acids like vinegar or lemon juice in water will also prevent browning of vegetables.
4. We can also rub the surface of cut fruits with juices of citrus fruits like lemon to avoid from browning.
5. Ascorbic acid can also be used to prevent browning.

Question 3.
What is the reason for browning of vegetables in our daily life?
Answer:

1. Some fruits and vegetables like potato and brinjal, when they cut react with oxygen in air.
2. The process of reaction with oxygen is called oxidation.
3. Due to this oxidation process, brown layer is formed on the surface of fruits and vegetables.

Question 4.
What are the harmful physical and chemical changes in environment?
Answer:

1. Plastic decomposition
2. Acid rains
3. Global warming
4. Oil spills in seas and rivers
5. Earthquakes and
6. Floods are some of the harmful physical and chemical changes in environment.

Question 5.
What changes might have we noticed in our daily life?
Answer:

1. The colour ,of tender leaf changing from red to green.
2. Hard raw fruit becoming soft ripen fruit.
3. Colour changes observed in slices of brinjal and apple after being cut.
4. Change of milk into the curd.
5. Ash produced on burning paper.
6. Raw rice becoming soft after cooking etc.

Question 6.
What questions would you pose to your teacher about changes around us?
Answer:

1. Why changes occur around us?
2. Why would we depend on changes in the nature?
3. What would happen if changes do not occur?
4. How changes in the nature influence us?

Question 7.

What type of change is it? Is itreversible? If so, how?
Answer:

1. Ice slowly melts and becomes water.
2. On further heating water changes to steam.
3. This is a physical change.
4. No new substance is formed.
5. The change is reversible. If we reduce the temperature the water vapour changes back to water when the temperature is further reduced, it changes to ice.
   

Question 8.
What are the characteristics of a physical change?
Answer:

1. No new substances are formed.
2. It is usually temporary and reversible in nature.
3. The chemical properties of a substance do not change.
4. Change in physical properties such as colour, shape and size of a substance may undergo a change.

Question 9.
What are the characteristics of a chemical change?
Answer:

1. During chemical change new substance are formed.
2. It is a permanent change and irreversible in nature.
3. Chemical composition of the substances changes.
4. Heat, light may be released or absorbed.
5. A colour change may take place and sound may be produced.

Question 10.
Where do you see the iron pilar that is not rusted for thousands of years? What are the reasons for that?
Answer:

1. We can see an iron pillar at the Qutub complex in Delhi which is not rusted. It is 1600 years old.
2. It is made by 98% wrought iron, a special type of iron that has 1% of phosphorous.
3. It don’t have Sulphur and Magnesium.
4. More over, the pillar is covered by a thin layer of compound called Misawitea.
5. So, rusting of this iron pillar is too slow and it will take thousands of years to get rusted.

Question 11.
What is so special about Lonar Lake?
Answer:

1. The Lonar lake in Buldhana district of Maharashtra was created by plummeting meteor about 5200 years ago.
   
2. The water of Lonar lake turned into pink colour recently due to Haloarchaea microbes present in the salty water.
3. But the colour is not permanent.
4. When the biomass of the microbes settled at the bottom, then the water again becomes transparent.

Questions 12.
Anurag appreciates the changes in ripe mango as “How nice its colour and taste are”? Give some examples of changes that makes you feel happy, or wonder.
Appreciate them in your own words.
Answer:

1. When mango ripens, the contents present in the fruit gives good taste. The change in colour indicates that the fruit is ripend.
2. Similar situations we experience with many fruits like banana, guava, papaya, pine apple … etc.
3. In fact fruits are a gift to human beings as they give instantaneous energy when eaten.
4. Nature is so kind to us to provide such ready made safe foods.

7th Class Science 10th Lesson Changes Around Us Long Questions and Answers

Question 1.
What is rust and rusting? Why does iron rust? What type of a change is this?
Answer:

1. When iron nails, iron gates, iron benches or pieces of iron are left is the open ground for a long time, we find a brown layer on the surface of iron articles.
2. This is called rust’ and process of forming this layer is called rusting.
3. When iron is exposed to air for a long time, the Oxygen present in air reacts with it in the presence of moist air and forms a new substance called iron oxide as rust on iron articles. This process is known as rusting.
   Iron + Oxygen (from air) + Water → rust (Iron oxide)
4. As a new substance is formed in this change, we call it a chemical change.

Question 2.
Answer the following questions.
The gas we use in kitchen is in the form of liquid in the cylinder. When it comes out from the cylinder it becomes a gas (step-I), then it burns (step-II).
Choose the correct statement from the following.
a. Only step – I is a chemical change.
b. Only step – II is a chemical change.
c. Both steps – I & II are chemical changes.
d. Both steps – I & II are physical changes.
Answer:
a) Step -1 – is a physical change (not a chemical change)
b) Step – II – is a chemical change (It is correct)

c) Both steps I & II – are chemical changes.
This is not correct.
Step – I – Physical change and
Step – II – Chemical Change is correct.

d) Both steps I & II – are physical changes – This is not correct.
Step I – Physical change
Step II – Chemical change.

Question 3.
What are periodic changes? Explain briefly.
Answer:

1.  If we observe that every change mentioned is the table repeats after some period of time.
2. Such changes are known as periodic changes.
3. The events which repeat at regular intervals of time are called periodic events.

Question 4.
What is Galvanisation? Explain its importance.
Answer:

1. Some articles made up of iron, don’t get rusted even they are exposed to air.
2. To prevent iron articles from coming into contact with oxygen in air or water or both, we deposit a layer of a metal like Chromium or Zinc on them.
3. This process of depositing a layer of zinc or Chromium on Iron is called Galvanisation.
4. Generally we use Zinc for such type of coatings.
5. We find in our house that water pipe lines are without rust on them.
6. If we observe carefully, we notice that there is some metallic coating on these pipes to prevent rusting.
7. They do not get rusted even after a long time since they are galvanized.
8. The process of depositing one metal on another metal is called galvanisation.

Question 5.
Write the environmental issues due to physical and chemical changes.
Answer:
Physical and chemical changes occur all around us. These changes are essential parts of our daily lives. However a few of the physical and chemical changes that occur daily are harmful to the environment.

For example

1. Plastic decomposition, global warming, effects of acid rain and oil spills, earthquakes, floods etc.
2. Plastic waste is a widely recognised source of pollution. Most plastics are non- biodegradable. They take hundreds of years to decompose. Hence their disposal causes pollution.
3. Global warming is due to drastic increase in the emission of carbon dioxide by the burning of fossil fuels. The climate change affects not only the atmosphere and living things on land but also creatures of ocean.
4. Acidic gases are produced when fossil fuels such as coal and oil are burned in power station, factories and homes.
5. Oil spills occur when liquid petroleum is released into the environment by human interference causing damage to creatures of ocean.
6. Changes are quite common in nature. Human beings are misusing the natural re-sources for their needs.
7. But we should take care that our needs should not bring drastic changes that causes harm to the nature and mankind.

AP Board 7th Class Science 10th Lesson 1 Mark Bits Questions and Answers Changes Around Us

I. Multiple Choice Questions

Choose the correct answer and write its letters in the brackets.

1. Change in the shape of balloon is done by bibwing air into it. This is a……
A) manmade change
B) natural change
C) chemical change
D) periodic change.
Answer:
A) manmade change

2. Which of the following is not a man made-change?
A) preparation of bricks
B) making of paper
C) weaving of clothes
D) growing of nails
Answer:
D) growing of nails

3. Which of the following is not a fast change?
A) burning of paper
B) firing of crackers
C) making of a cake
D) spinning of a top
Answer:
C) making of a cake

4. The change happens in less time is.
A) slow change
B) fast change
C) periodic change
D) non periodic change.
Answer:
B) fast change

5. Which of the following is not reversible?
A) Weight suspended from a spring
B) Water changed to water vapour
C) Inflating of a balloon
D) Burning of a coal
Answer:
D) Burning of a coal

6. On …………… ice converts to water
A) heating
B) cooling
C) freezing
D) evaporating
Answer:
A) heating

7. some changes we cannot regain the original substance, these are.
A) manmade change
B) natural change
C) irreversible change
D) reversible change
Answer:
C) irreversible change

8. Limewater
A) Calcium Hydroxide
B) Sodium hydroxide
C) Potassium hydroxide
D) Carbonic acid
Answer:
A) Calcium Hydroxide

9. Which of the following is an irreversible change?
A) burning of wood
B) burning of Diwali crackers
C) ripening of fruits
D) all
Answer:
D) all

10. Which gas is released when lemon juice reacts with baking soda?
A) oxygen
B) carbon dioxide
C) nitrogen
D)water vapour
Answer:
B) carbon dioxide

11. These changes are repeating at regular intervals of time.
A) slow change
B) fast change
C) periodic change
D) non periodic change.
Answer:
C) periodic change

12. Changes which do not occur at regular intervals of time and which cannot be predicted are called
A) slow change
B) fast change
C) periodic change
D) non periodic change
Answer:
D) non periodic change

13. Crystallization requires
A) heating
B) cooling
C) evaporating
D) A or C
Answer:
A) heating

14. In crystallization….
A) no new substances are formed.
B) new substances are formed.
C) no heating is required
D) none
Answer:
A) no new substances are formed.

15. Crystallization is
A) chemical change
B) physical change
C) periodic change
D) non periodic change
Answer:
B) physical change

16. Choose correct answer.
S: Crystallization is a Physical Change.
R: In crystallization no new substances are formed.
A) S and R are correct.
B) S and R are incorrect.
C) S is correct and R is incorrect.
D) S is incorrect and R is correct.
Answer:
A) S and R are correct.

17. Which change takes place when ice cube melts?
A) colour
B) phase
C) chemical
D) all
Answer:
B) phase

18. When a piece of gold is melted?
A) no new substances are formed.
B) new substances are formed.
C) chemical composition changes
D) none
Answer:
A) no new substances are formed.

19. When a piece of gold is melted, its chemical composition in the Solid form and also in the liquid form.
A) changes
B) varies
C) remains same
D) different
Answer:
C) remains same

20. In physical change ……….. changes.
A) shape
B) colour
C) size
D) all
Answer:
D) all

21. It is not a characteristic of a physical change…
A) No new substances are formed
B) Temporary and reversible in nature.
C) The chemical properties of a substance do not change.
D) It is a periodic change.
Answer:
D) It is a periodic change.

22. In curdling of milk is
A) a physical change
B) reversible change
C) chemical change
D) temporary change
Answer:
C) chemical change

23. When magnesium burns in the presence of oxygen, it forms magnesium oxide
A) magnesium oxide
B) magnesium chloride
C) carbon dioxide
D) none
Answer:
A) magnesium oxide

24. Magnesium Hydroxide is…..
A) an acid
B) a base
C) a neutral
D) none
Answer:
B) a base

25. Characteristic of a chemical change
A) During chemical change new substances are formed.
B) It is a permanent change and irreversible in nature.
C) Chemical composition of the substance changes.
D) All
Answer:
D) All

26. In chemical change which is not happens.
A) Heat, light may be released or absorbed.
B) A colour change may take place and sound may be produced.
C) Original substances may be formed on reversing the process
D) None
Answer:
C) Original substances may be formed on reversing the process

27. Rusting of iron requires
A) moisture
B) air
C) both
D) none
Answer:
C) both

28. Rust is…
A) iron oxide
B) calcium chloride
C) iron peroxide
D) above all
Answer:
A) iron oxide

29. Oxidization is observed in
A) iron articles
B) apples
C) brinjal
D) none
Answer:
D) none

30. Which of the following is used to prevent browning of the outer surface of the potato and brinjal?
A) cold water
B) lemon juice
C) ascorbic acid
D) above all
Answer:
D) above all

31. Which of the following is used in galvanizing?
A) zinc
B) chromium
C) A & C
D) none
Answer:
C) A & C

32. This process of deposition of a layer of zinc on iron is called
A) oxidation
B) galvanization
C) crystallization
D) none
Answer:
B) galvanization

33. Due to this process of brown layer is formed on the surface of fruits and vegetables.
A) oxidation
B) galvanization
C) crystallization
D) none
Answer:
A) oxidation

34. Which of the following is a useful change?
A) global warming
B) acid rain
C) plastic decomposition
D) fermentation
Answer:
D) fermentation

35. Which of the following occurs due to drastic increase in the emission of carbon dioxide by the burning of fossil fuels
A) global warming
B) floods
C) earth quakes
D) fermentation
Answer:
A) global warming

36. Ice converting to water, water converting to steam are ………. changes.
A) reversible
B) chemical
C) periodic
D) all
Answer:
A) reversible

37. Ripening of fruits is ………….. change.
A) reversible
B) physical
C) periodic
D) irreversible
Answer:
D) irreversible

38. The change occurs only in Size, colour and shape of the substance and no change in chemical composition are called ………….. changes
A) chemical
B) physical
C) periodic
D) irreversible
Answer:
B) physical

39. ………. change occurs with the formation of new substance in different chemical composition.
A) Reversible
B) Physical
C) Periodic
D) Chemical
Answer:
D) Chemical

40. The process of depositihg zinc on iron metals is called
A) oxidation
B) galvanization
C) rusting
D) crystallization
Answer:
B) galvanization

II. Fill in the blanks.

1. The changes which were taken place by the involvement of human beings are called ………………. change.
2. Changes which occur in ………………. duration of time are called fast changes.
3. Changes which takes longer duration of time to happen are called ………………. Change.
4. Changing of vegetable to curry : slow reaction:: changing of acid into vapour ………………. .
5. On ………………. water converts to ice.
6. The changes in which the formed substance can be converted into their ………………. are called reversible changes.
7. ………………. changes Limewater into milky white.
8. Vinegar + Baking Soda → Sodium acetate + ………………. + water
9. ………………. + Lime water → Calcium carbonate + water
10. Changes in which we cannot get the original substance by reversing the experimental conditions are called ………………. Changes.
11. ………………. changes are repeating at regular intervals of time .
12. The process of separating a soluble solid from the solution by heating or evaporating is called ………………. .
13. A ………………. is usually temporary and reversible in nature.
14. The substances which undergo change in colour or state or size or shape are ………………. .
15. When a Magnesium ribbon burns it gives ………………. light leaving a powdery substance behind.
16. ………………. + Water → Magnesium Hydroxide
17. Changes that occur with the formation of new substance with different chemical composition or transformation of a substance into another substance with the evolution or absorption of heat or light energy are termed as ………………. .
18. Iron + Oxygen (from air) + Water → ……………….
19. Apply a coat of paint or grease on iron articles. Prevents ………………. .
20. To prevent iron articles from coming contact with oxygen in air and water, a layer of another metal like ………………. is coated on them.
21. The process of deposition of a layer of zinc on iron is called ………………. .
22. Browning is not only observed on iron articles but also on cut fruits and ………………. .
23. Rubbing of the surface of cut fruits with ………………. to avoid from browning.
24. The process of reaction with ………………. is called oxidation.
25. ………………. waste is a widely recognized source of pollution.
26. ………………. gases are produced when fossil fuels such as coal and oil are burned in power station, factories and homes.
27. Oil spills occur when ………………. is released into the environment.
28. Formation of day and night, occurrence of seasons are ………………. changes.
29. Curding of milk : useful changes :: ………………. : harmful change.
Answer:

1. 1. man-made
2. short
3. slow
4. fast reaction
5. cooling
6. original substance
7. Carbon dioxide
8. carbon dioxide
9. Carbon dioxide
10. irreversible
11. periodic changes
12. crystallization
13. physical change
14. physical changes
15. brilliant white dazzling
16. Magnesium Oxide
17. chemical change
18. rust (Iron oxide)
19. rusting of iron
20. chromium or zinc
21. Galvanization
22. vegetables
23. juices of citrus fruits
24. oxygen
25. Plastic
26. Acidic
27. liquid petroleum
28. periodic
29. global warming

III. Match the following.

1.

Answer:

2.

Answer:

3.

Answer:

4.

Answer:

5.

Answer:

Do You Know?

→ Belum caves are naturally formed caves located near Kolimigundla mandal of Kurnool district. These are the second largest caves in Indian subcontinent after Meghalaya state caves. The name is derived from Bilum” Sanskrit word for caves. The caves reach its deepest point (120 feet from entrance level) at the point known as “Paathalaganga” only 1.5 km is open to tourists. In 1988 Andhra Pradesh Tourism , Development Corporation (APTDC) declared them protected and developed the caves as a tourist attraction in February 2002. Borra Caves are also famous natural caves located at Visakhapatnam District.

→ The Lonar lake in Buldhana district of Maharashtra was created by plummeting meteor about 5200 years ago. The water of Lonar lake turned into pink colour recently due to Haloarchaea microbes present in the salty water. But the colour is not permanent. When the biomass of the microbes settled at the bottom, then the water again becomes transparent.

→ The Iron pillar at Delhi :
Amazingly there is an iron that did not rust! There is an iron pillar at the Qutub complex in Delhi which is more than 1600 years old. Even after such a long period, the iron pillar kept in open space has hot rusted at all. Do you know how? It is made by wrought iron which contains more amounts of phosphorus than usual. The main reason for rust resistance is due to the formation of Iron hydrogen phosphate on its surface. So its takes more time to rest. That’s why still the iron pillar at Delhi did not get rust.

These AP 7th Class Science Important Questions 9th Lesson Heat, Temperature and Climate will help students prepare well for the exams.

AP Board 7th Class Science 9th Lesson Important Questions and Answers Heat, Temperature and Climate

Question 1.
What is heat?
Answer:
Heat is a form of energy which flows from hotter body (higher energy) to cooler body (lower energy).

Question 2.
How is heat measured?
Answer:
Heat is measured in Joules or calories with calorimeter.

Question 3.
What is temperature?
Answer:
The degree of hotness or coldness is called temperature.

Question 4.
How do we call the variations of hotness, coldness?
Answer:
The variations of hotness, coldness can be termed as degree of hotness and coldness.

Question 5.
What are the units of temperature?
Answer:
Temperature is measured in degrees of Celsius, degrees of Fahrenheit or Kelvin using a thermometer.

Question 6.
What is the SI unit of temperature?
Answer:
The SI unit of temperature is kelvin (K).

Question 7.
Write the different modes of transfer of heat?
Answer:

1. Conduction of heat
2. Convection of heat
3. Radiation of heat.

Question 8.
What is conduction?
Answer:
The process of transfer of heat from hotter to colder end through the conductor is called conduction.

Question 9.
What is convection of heat?
Answer:
The process of transfer of heat from source of heat to surface by the motion of par¬ticles is called “convection of heat”.

Question 10.
What is radiation of heat?
Answer:
The process of transfer of heat in the form of waves is called radiation.

Question 11.
What is thermal contact?
Answer:
The contact which transfers heat by any mode is called Thermal contact.

Question 12.
What is the condition for conduction of heat?
(OR)
When does conduction take place?
Answer:
Conduction takes place, only when the conductor is in touch (contact) with the source of heat. The contact which transfers heat by any mode is called Thermal contact. Conduction doesn’t take place without thermal contact.

Question 13.
What are called convectional currents?
Answer:
Heat is transferred by means of currents called convectional currents.

Question 14.
How does heat transfer in liquids and gases?
Answer:
In liquids and gases heat is transmitted by mode of convection of heat.

Question 15.
What is a medium?
Answer:
The material which helps in transfer of heat from one place to another is called a medium. Solid, liquid and gaseous substances act as medium for transfer of heat.

Question 16.
How does heat transfer if there is no medium?
Answer:
Heat transfer, in the form of waves from one place to another. It does not require any medium.

Question 17.
Write one application of radiation of heat.
(OR)
How does a thermal scanner work?
Answer:
The thermal scanner receives the heat in the form of radiation to measure our body temperature.

Question 18.
What happens if we heat and cool a metal?
Answer:
The metal expands on heating and contracts on cooling.

Question 19.
Which device is used to measure the temperature?
Answer:
Thermometers are used to measure temperature. .

Question 20.
Based on which principle a Thermometer does work?
Answer:
Thermometer works on the expansion of liquids (mercury).

Question 21.
Where the thermometers are used?
Answer:
People use thermometers in homes, hospitals, automobiles, industries and restaurants etc., to measure temperatures of different objects and substances.

Question 22.
Which is essential for our healthy living? (OR) Why should we protect environment?
Answer:
A clean environment is essential for heaithy living. So, we want a concrete plan to protect environment.

Question 23.
Why does alcohol use in thermometer? (OR)How can a alcohol thermometer mea-sures very low temperatures?
Answer:
The freezing point of alcohol is less than -100°C. So, it can be used to measure very low temperatures.

Question 24.
Write the different types of thermometers?
Answer:
The different types of thermometers are Clinical Thermometer, Laboratory Thermometer, Digital Thermometer and Six’s makimum and minimum thermometer.

Question 25.
Which instrument is used to measure the maximum (highest) and minimum (lowest) temperatures of a place in a day?
Answer:
Six’s maximum and minimum thermometer is one of the Meteorological Instruments used to measure maximum (highest) and minimum (lowest) temperatures of a place in a day.

Question 26.
What is the normal temperature of the human body?
Answer:
The normal temperature,of the human body is 37°C or 98.4°F.

Question 27.
Why does smoke and hot air move up?
Answer:
Smoke and hot air moves up because it expands and becomes lighter. . .

Question 28.
What is the use of ventilators in our house?
Answer:
Smoke and hot air moves up because it expands and becomes lighter through ventila¬tors and exhaust fans on the upper parts of the wall.

Question 29.
What happens to the air on heating?
Answer:
On heating, the air expands, occupying more space and becomes lighter.

Question 30.
What happens when air is compressed?
Answer:
The air pressure becomes more when air is compressed.

7th Class Science 9th Lesson Heat, Temperature and Climate Short Questions and Answers

Question 1.
When do we feel hot and cool?
Answer:

1. The heat when heat energy flows from hotter body to our body. We feel hot. Here we gain heat energy from the hotter body.
2. We feel cool, when heat energy flows from our body to colder body. Here, we lose heat energy.

Question 2.
How does heat flow? How do we determine its direction?
Answer:

1. Heat flows from a body of high temperature to a body of low temperature.
2. This direction is determined by temperature. ‘

Question 3.
How do we written degree of Celsius, degree of Fahrenheit and Kelvin?
Answer:

1. Degree Celsius: Celsius is written as °C and read as degree Celsius.
2. Degree Fahrenheit: Fahrenheit is written as °F and read as degree fahrenheit.
3. Kelvin is written as K and read as Kelvin.

Question 4.
What is Air pressure? How does it measure? What are the effects of the air pres-sure?
Answer:
Air pressure:
The force applied by air on any surface in contact is called “air pressure”.

Measuring of air pressure:
Air pressure is measured in height of mercury level in centimeters, and it is measured with a barometer. Now a days aneroid barometers are used to measure air pressure.

Effects of air pressure:
The air pressure becomes more when it is compressed. When air expands and rises up it creates low pressure, which drives the air high pressure from surrounding to move and occupy that place.

Question 5.
Why are cooking utensils made of metals while their handles are made of plastic or wood?
Answer:

1. Some materials allow heat through them, this property is called conductivity.
2. We use metals to make cooking vessels because they allow heat through them.
3. We use material which does not allow heat to pass through as handles.
4. So, cooking utensils made of metals while their handles are made of plastic or wood.

Question 6.
Write four applications of expansion of metals on heating.
Answer:

1. The electric power lines (wires) are held loose on poles
2. Rollers are kept under the beams of metal bridges
3. Mercury is used in thermometers
4. Small gaps are left between rails in railway tracks

Question 7.
Write the different modes of transfer of heat?
Answer:
Transfer of heat is in different types of materials. Heat gets transferred in three different modes, They are

1. Conduction of heat
2. Convection of heat
3. Radiation of heat

1) Conduction of heat:
This process of transfer of heat from hotter to colder end through the conductor is called conduction. This mode of transfer of heat happens more in solid conductors.

2) Convection of heat:
This process of transfer of heat from source of heat to surface by the motion of particles is called “convection of heat”. In liquids and gases heat is transmitted by mode of convection of heat.

3) Radiation of heat:
This process of transfer of heat in the form of waves is called radiation. Radiation does not need any material medium. Sun’s heat transfers to earth in the form of radiation.

Question 8.
Write the differences between good conductors and poor conductors?
Answer:

Question 9.
How does a thermos flask work?
(OR)
Describe working of a thermos flask.
Answer:

1. Thermos flaSk has a two layered glass container and the air between these layers is removed to create vacuum.
2. The inner silver coating protects the contents (tea, coffee, milk) poured in the flask from losing heat through radiation.
3. As there is no medium between the walls of the flask. Neither conduction nor con-vection of heat takes place.
4. As a result, heat is not transferred outside the flask so it is retained inside the flask for a few hours.

Question 10.
What is the reason for in the expansion of rails, mercury in thermometer, air inside the puri etc?
Answer:

1. This is due to increase in the energy of particles present in these substances.
2. Particles of substances occupy more space when they get heated.
3. This is the reason for in the expansion of rails, mercury in thermometer, air inside the puri etc.

Question 11.
How does hot air balloon work?
Answer:

1. Warm air is lighter than cold air.
2. This property of air is used in flying of hot air balloons,
3. It contains a bag which is called as envelope, and it is filled with heated air.
4. There is a basket under the envelope which carries passengers and a source of heat.

Question 12.
Why mercury is used in thermometers?
Answer:
Mercury is used in thermometers, because it has the best properties to measure temperature.
Those are

1. It’s expansion is uniform.
2. It is bpaque and shining.
3. It does not stick to the sides of glass tube.
4. It is a good conductor of heat.
5. It has a high boiling point (357°C) and a low freezing point (-39°C). Hence a wide range of temperatures can be measured using a mercury.

Question 13.
Why alcohol is used in thermometers?
Answer:
Alcohol is used in thermometers, because it has the best properties to measure temperature. Those are

1. The freezing point of alcohol is less than -100°C.
2. So, it can be used to measure very low temperatures.
3. It’s expansion per degree Celsius rise in temperature is very large.
4. It can be colored brightly and hence is easily visible.

Question 14.
What are the melting point of ice and boiling point of water in different scales?
Answer:
1) Celsius scale :
Melting point of ice is 0°C and boiling point of water is 100°C

2) Fahrenheit scale :
Melting point of ice is 32°F and boiling point of water is 212°F

3) Kelvin scale :
Melting point bf ice is 273K and boiling point of water is 373K

Question 15.
Write the Formulas for temperature conversion 1) Celsius to Fahrenheit 2) Celsius to Kelvin.
Answer:

Question 16.
Explain two applications of transfer of heat.
Answer:
Thermal scanning:
The thermal scanner receives the heat in the form of radiation to measure our body temperature.

Thermos flask:
It has a two layered glass container and the air between these layers is removed to create vacuum. The inner silver coating protects the contents (tea, coffee, milk) poured in the flask from losing heat through radiation. As there is no medium between the walls of the flask. Neither conduction nor convection of heat takes place. As a result, heat is not transferred outside the flask so it is retained inside the flask for a few hours.

Question 17.
Fill in the table with suitable answers.

Answer:

Question 18.
What is the use of a Clinical Thermometer? How it convenient to record the reading?
Answer:

1. Clinical Thermometer is used in hospitals to measure the temperature of the human body.
2. It has a kink that prevents the mercury from flowing back into the bulb when it was taken out of the patient’s mouth.
3. This helps to record the temperature conveniently.

Question 19.
Where a Laboratory Thermometer is used? How it is better than the clinical ther-mometer?
(OR)
Describes laboratory Thermometer.
Answer:

1. Laboratory Thermometer is used in school labs, industries etc. to measure temperature. It has no kink.
2. It is made of a long stem and the bulb of mercury, so it can measure higher tempera-tures than clinical thermometer.

Question 20.
How does a Digital Thermometer work?
Answer:

1. Digital Thermometer works without Mercury.
2. It has a display which shows readings directly.
3. It is very easy to use it, we can use it by just pressing on/off button present on it.
4. Even children can also handle this one.

Question 21.
How do you use a clinical thermometer and a laboratory thermometer?
Answer:
Clinical thermometer

1. Wash the clinical thermometer properly with an antiseptic solution.
2. To lower the mercury level, hold the thermometer firmly and give some jerks.
3. Ensure that it falls below 35°C. Now place the bulb of the thermometer under your tongue.
4. After one or two minutes, take the thermometer out and note the reading.
5. This is your body temperature.
6. Don’t hold the thermometer by the bulb while reading it.

A Laboratory thermometer:

1. Take cold or hot water in a bowl. Place the mercury bulb of the thermometer in the water so that the bulb immerses in it.
2. Wait for some time till the mercury level shows a constant reading.
3. Note down that reading.

Question 22.
How does sunstroke occur?
(OR)
What happens when humidity increases in the air?
Answer:

1. Evaporation of sweat from our body makes us cool to maintain our body temperature.
2. In summer, the humidity of air is high. Due to high humidity and temperature, it becomes difficult to evaporate the sweat from our body to cool It down.
3. But still our body losses water.
4. High temperatures, along with humidity sometimes may cause heat stroke or sun¬stroke.

Question 23.
What is the first aid for sunstroke?
Answer:
First Aid for sunstroke :

1. Call 108 immediately. Move the victim to a cool ventilated place.
2. Then loosen his dress and remove extra clothing. Put a cold wet towel on his head, back of the neck, on the grain and under the armpits.
3. Fan air over the patient while wetting their skin with water from a sponge or wet cloth. Give plenty of cool, lightly salted water to drink often but in small sips.
4. Help the person stay calm without any anxiety.

Question 24.
What is weather of a place? What are its measuring components?
Answer:

1. The day-to-day variations in the components like temperature, humidity, rainfall, wind speed are called weather.
2. Maximum and minimum temperature of a day, air pressure, rainfall, wind speed and humidity are called measuring components of weather.

Question 25.
How do Meteorologists decide the climate of the place?
Answer:

1. Meteorologists (scientists who study and work on weather) record weather every day. .
2. These records of the weather have been preserved for the past several decades.
3. They help us to determine the weather pattern of a place.
4. The average weather pattern taken over a long period, say 25 years or more, is called the climate of the place.

Question 26.
Why does climate affect pur life style? What are its measuring components?
Answer:

1. Climate of a place remains unchanged for a long period of time. So, it affects our lifestyle.
2. The measuring components of climate are maximum and minimum temperature of a day, air pressure, rainfall, wind speed and humidity.

Question 27.
What are the differences between weather and climate?
Answer:

Question 28.
How weather and climate is effected our life?
Answer:

1. Daily weather and long-term climatic conditions influence the life style of humans and other living things directly and indirectly.
2. Some of them are diet, clothing, housing, occupations etc.

Question 29.
Doctor put the thermometer in the mouth of Karthikeya’s sister, Neha. By seeing this Karthikeya got some doubts and asked doctor. What could be those doubts?
Answer:

1. What is in the thermometer?
2. How does it show the temperature?
3. How can you say Neha got the fever?
4. How much time shall it place in the mouth?

Question 30.
Guess what will happen if we use the clinical thermometer to measure the temperature of the ice cubes or boiling water?
Answer:
We cannot measure too low and too high temperatures by using a clinical thermometer. It is made for clinical use only, so by using this we can measure from 35°C to 42°C only. If we measure temperature of boiling water or ice cubes it will break or it does not work.

Question 31.
Guess what will happen if a low air pressure is formed in your area?
Answer:
If a low air pressure is formed in our area, air blow from high air pressure area to occupy the low air pressure area. Sometimes this wind causes damage to roofs, trees etc.

Question 32.
Kalyan said that the climate was changed by being seen the dark clouds in the sky. Is the word climate correct in his statement?
Answer:
No. climate is different from weather. The changes occur during the period of some hours is called changing in weather. Climate is average weather conditions of a long period. So he had to use weather instead of climate in his statement.

Question 33.
What will happen, if there is no kink in the clinical thermometer?
Answer:
The kink prevents the mercury from flowing back into the bulb when it was taken out of the patient’s mouth. This helps to record the temperature conveniently. If there is no kink the level of the mercury will fall down in the gap of taking out from the patient and seeing the reading. So, it may show incorrect reading.

Question 34.
What is your observation in the activity of metal spoon with fixed pins and a candle and write the reason.
Answer:
I will observe the dropping of pins one after another from the flame end of the spoon. This is due to the transfer of heat from the end kept in the flame (hotter end) towards your hand (colder end) through a spoon (metal).

Question 35.
What are your observations in the activity of expansion of metal on heating?
Answer:
I will observe movement in the straw. The needle rolls on the second block of wood because of the expansion of the cycle spoke. If we remove the candles the needle rolls back causing movement in the straw opposite to the previous motion.

Question 36.
Read the graph and answer the following questions.

1. Which component was shown in the graph?
Answer:
Temperature

2. On which day the maximum temperatures recorded?
Answer:
On the dates, 1-12-2020 and 2-12-2020 the maximum temperature was recorded.

Question 37.
Take a glass and keep a postcard oh it. Wave your notebook above the post card to displace the air just above the postcard. What is your observation? What is the reason for it?
Answer:
The moving air creates low pressure. Hence the postcard lifts up due to the higher pressure on the card from air inside the glass.

Question 38.
Observe the figure and give answers to the following questions.
1. What mode of transfer of heat is observed in the spoon?
2. What is the source of heat?
3. What will happen after some time?
4. What is the medium here?

Answer:
1. Conduction of heat is observed in the spoon
2. Candle is the source of heat.
3. All the pins will fall down.
4. Metal in the spoon is the medium (solid)

Question 39.
Fill in the table with suitable answers.

Answer:

Question 40.
Fill in the table with suitable answers.

Answer:

Question 41.
Draw the diagram of mercury laboratory thermometer.
Answer:

Question 42.
Draw the diagram of alcohol laboratory thermometer.
Answer:

Question 43.
Draw the diagram of a thermos flask and label its inner parts.
Answer:

44. Draw the diagram showing the arrangement of apparatus to show the expansion of liquids on heating?
Answer:

45. Draw the diagram of Six minimum and maximum temperatures and label the parts.
Answer:

7th Class Science 9th Lesson Heat, Temperature and Climate Long Questions and Answers

Question 1.
Compare different modes of transfer of heat.
Answer:

Question 2.
Write about different types of thermometers.
Answer:
Clinical thermometer:

1. Wash the clinical thermometer properly with an antiseptic solution.
2. To lower the mercury level, hold the thermometer firmly and give some jerks.
3. Ensure that it falls below 35°C. Now place the bulb of the thermometer under your tongue.
4. After one or two minutes, take the thermometer out and note the reading.
5. This is your body temperature.
6. Don’t hold the thermometer by the bulb while reading it.

Laboratory thermometer:

1. Take cold or hot water in a bowl. Place the mercury bulb of the thermometer in the water so that the bulb immerses in it.
2. Wait for some time till the mercury level shows a constant reading.
3. Note down that reading.

Digital Thermometer:

1. It works without mercury.
2. It has a display which shows readings directly.
3. It is very easy to use it.
4. We can use it by just pressing on/off button present on it.
5. Even children can also handle this one.

Six’s maximum and minimum thermometer:

1. It is one of the Meteorological Instruments used to measure maximum (highest) and minimum (lowest) temperatures of a place in a day.
2. It has a cylindrical ‘Bulb A’, and ‘Bulb B’ connected through a ‘U-shaped tube’ con¬taining mercury.
3. Bulb A contains alcohol, and bulb B contains alcohol and its vapours.
4. When the temperature increases, the alcohol in the bulb A expands and pushes the mercury in the U tube, this makes indicator(M) to move up.
5. This indicates the maximum temperature of the day.
6. When the temperature decreases, alcohol in the bulb A contracts and pulls the mercury back.
7. This makes indicator (N) to move up.
8. This indicates the minimum temperature of the day.
9. After taking readings the indicators M and N are brought to their original places by using a magnet.

Question 3.
What is humidity? How does it measure? How does it affect or body? What is the first aid of sunstroke?
Answer:
HumidityAll the evaporated water from different water bodies go into air. This water vapour present in the air is called humidity.

Measurement of humidity:
Hygrometer is used to measure humidity in air and it is expressed in grams per cubic meter.

Effects of humidity:
Evaporation of sweat from our body makes us cool to maintain our body temperature. In summer, the humidity of air is high. Due to high humidity and temperature, it becomes difficult to evaporate the sweat from our body to cool it down. But, still our body losses water. High temperatures, along with humidity sometimes may cause heat stroke or sunstroke.

First Aid for sunstroke:
Call 108 immediately. Move the person out of the heat. Fan while spraying water to cool him. Let the person drink water to rehydrate.

Question 4.
Read the following table and answer the questions.

i) At what temperature, the ice melts? Express in Celsius.
ii) Which measurements are given in the table?
iii) Convert, 100°C into Fahrenheit and kelvin scale.
iv) What are the SI units of temperature?
Answer:
i) 0°C .
ii) Measurements of temperature are given.
iii) 100°C =212°F =373K
iv) Kelvin

Question 5.
How do you appreciate the weather reports?
Answer:

1. The day-to-day variations in the components like temperature, humidity, rainfall, , wind speed are called weather.
2. It keeps on changing and changes are very fast too.
3. One day it may be dry and sunny and the next day it may rain.
4. It gives the information about atmospheric conditions in a specific area and time.
5. We can get details of weather from weather reports and you can see these symbols on television, newspapers and in weather forecasting.
6. Weather forecasting is the application of science and technology to predict the conditions of the atmosphere using components of weather for a given location and time.
7. Weather reports are very useful to farmers, fishermen etc.
8. So I appreciate the weather reports.

Question 6.
How do you appreciate the properties of the mercury and alcohol as they are used in the thermometers?
Answer:
Properties of mercury:

1. Its expansion is uniform.
2. It is opaque and shining.
3. It does not stick to the sides of glass tube.
4. It is a good conductor of heat.
5. It has a high boiling point (357°C) and a low freezing point (-39°C).

Hence a wide range of temperatures can be measured using mercury.

Properties of alcohol:

1. The freezing point of alcohol is less than -100°C. So, it can be used to measure very low temperatures.
2. It’s expansion per degree Celsius rise in temperature is very large.
3. It can be coloured brightly and hence is easily visible.

Hence a wide range of temperatures can be measured using alcohol. Clinical ther-mometers, laboratory thermometers, six minimum and maximum thermometers etc. are made with alcohol or mercury or both.

Hence I appreciate the properties of the mercury and alcohol as they are used in the thermometers

AP Board 7th Class Science 9th Lesson 1 Mark Bits Questions and Answers Heat, Temperature and Climate

I. Multiple Choice Questions

Choose the correct answer and write its letters in the brackets.

1. It is a form of energy that flows from a hotter body to a cooler body.
A) Heat
B) Light
C) Sound
D) Electricity
Answer:
A) Heat

2. When heat energy flows from our body to Lassi. Here,
A) Lassi loss Heat energy
B) Body lose heat energy
C) Body gain heat energy
D) A and C
Answer:
B) Body lose heat energy

3. Joules are units of
A) Humidity
B) Climate
C) Heat
D) Air pressure
Answer:
C) Heat

4. The degree of hotness or coldness is called ………..
A) Humidity
B) Temperature
C) Heat
D) Air pressure
Answer:
D) Air pressure

5. Temperature is measured in…….
A) Degrees of Celsius
B) Degrees of Fahrenheit
C) Kelvin
D) All
Answer:
D) All

6. The SI unit of temperature is ………….
A) Degrees of Celsius
B) Degrees of Fahrenheit
C) Kelvin
D) All
Answer:
C) Kelvin

7. Kelvin is written as
A) °C
B) °F
C) °K
D) K
Answer:
D) K

8. Which is correct?
i) Heat is the degrees of hotness or coldness.
ii) Heat is measured in joules
A) i only
B) ii only
C) both i & ii
D) both are incorrect
Answer:
B) ii only

9. Cooking utensils are made of ………..
A) conductors
B) insulators
C) fuels
D) none of the above
Answer:
A) conductors

10. Handles of cooking vessels are made of …………….
A) conductors
B) insulators
C) fuels
D) none of the above
Answer:
B) insulators

11. A: Metals are used to make cooking vessels.
R: Metals allow heat through them.
Which is correct?
A) A & R are correct and R supports A
B) A & R are correct but R does not support A
C) A is correct but R is wrong
D) R is Correct but A is wrong
Answer:
A) A & R are correct and R supports A

12. The ability of a material to conduct heat is called …………..
A) Thermal conductivity
B) Thermal resistivity
C) Thermometer
D) None
Answer:
A) Thermal conductivity

13. It is not a good conductor.
A) Copper
B) Steel
C) Plastic
D) Cast iron
Answer:
C) Plastic

14. Insulator is….
A) Water
B) Glass
C) Plastic
D) All
Answer:
D) All

15. Heat cannot pass in the mode of
A) Conduction
B) Convection of heat
C) Radiation of heat
D) None
Answer:
D) None

16. In which heat is transferred from one end to another end by the mode of conduction.
A) Steel spoon
B) Water
C) A and B
D) Sun to earth
Answer:
A) Steel spoon

17. This mode of transfer of heat happens more in solid conductors
A) Conduction
B) Convection of heat
C) Radiation of heat
D) None
Answer:
A) Conduction

18. This process of transfer of heat from source of heat to surface by the motion of particles
A) Conduction
B) Convection of heat
C) Radiation of heat
D) all
Answer:
B) Convection of heat

19. This is not a medium of heat energy.
A) Solid
B) Liquid
C) Gas
D) None
Answer:
D) None

20. This mode of transfer of heat doesn’t require any media.
A) Conduction
B) Convection of heat
C) Radiation of heat
D) All
Answer:
C) Radiation of heat

21. The process of transfer of heat in the form of waves is called
A) Conduction
B) Convection of heat
C) Radiation of heat
D) All
Answer:
C) Radiation of heat

22. Which instrument can control the transfer of heat (loss of heat)?
A) Thermos flask
B) Thermometer
C) Thermal scanner
D) All
Answer:
A) Thermos flask

23. The flask retains hot inside the flask for
A) a few hours
B) ever
C) never
D) a few weeks.
Answer:
A) a few hours

24. Thermos flask was invented by
A) Sir James cook
B) Sir James Chadwick
C) Sir James Dewar
D) Sir James watts
Answer:
C) Sir James Dewar

25. Which of the following expands on heating and contracts on cooling?
A) Solid
B) Liquid
C) Gas
D) All
Answer:
D) All

26. Air on cooling
A) contracts
B) occupy less space.
C) expand
D) A and B
Answer:
D) A and B

27. Warm air is lighten than cold air. This property of air is used in
A) hot air balloons
B) kites
C) rockets
D) all
Answer:
A) hot air balloons

28. Thermometer contains bulb of
A) mercury
B) alcohol
C) A or B
D) silver
Answer:
C) A or B

29. Mercury is a in room temperature.
A) solid
B) liquid
C) gas
D) all
Answer:
A) solid

30. This is not a property of the mercury .
A) Its expansion is uniform.
B) It is a good conductor of heat.
C) It easily sticks to the sides of glass tube.
D) It has a high boiling point.
Answer:
C) It easily sticks to the sides of glass tube.

31. The boiling point and a freezing point of the mercury are
A) -39°C and 357°C
B) 357°C and-39°C
C)100°C and 0°C
D) none
Answer:
B) 357°C and-39°C

32. A: The freezing point of alcohol is more than -100°C.
R: Alcohol can be used to measure very low temperatures.
A) A & R are correct and R supports A
B) A & R are correct but R does not support A
C) A is correct but R is wrong
D) R is correct but A is wrong
Answer:
D) R is correct but A is wrong

33. Number of divisions in Fahrenheit scale is
A) 100
B) 212
C) 180
D) 32
Answer:
C) 180

34. Number of divisions in Kelvin scale is
A) 100
B) 212
C) 180
D) 32
Answer:
A) 100

35. Number of divisions in Celsius scale is
A) 100
B) 212
C) 180
D) 32
Answer:
A) 100

36. Which prevents the mercury from flowing back into the bulb in clinical thermometer.
A) Capillary
B) Kink
C) Bulb
D) Magnet
Answer:
B) Kink

37. Laboratory thermometer can measure higher temperatures than clinical thermometer because, it has
A) long bulb
B) long stem
C) short bulb
D) short stem
Answer:
B) long stem

38. This thermometer can work without Mercury.
A) Six max and min thermometer
B) Digital Thermometer
C) Clinical thermometer
D)All
Answer:
B) Digital Thermometer

39. Who invented Six’s maximum and minimum thermometer in 1780?
A) Sir James cook
B) James watt
C) Sir James Dewar
D) James Six
Answer:
D) James Six

40. The correct order is
i) After one or two minutes, take the thermometer out and note the reading,
ii) Place the bulb of the thermometer under your friend’s tongue.
iii) Wash the clinical thermometer properly with an antiseptic solution.
iv) To lower the mercury level, hold the thermometer firmly and give some jerks.
A) iv, ii, i, iii
B) iv, iii, ii, i
C) iii, iv, ii, i
D) ii, iii, iv, i
Answer:
C) iii, iv, ii, i

41. The normal temperature of the human body is
A) 37°C
B) 98.4°F
C) 310K
D) all
Answer:
D) all

42. Ventilators are working on
A) Air expands on heating
B) Air contracts on heating
C) Metal expands on heating
D) Air contracts on cooling
Answer:
A) Air expands on heating

43. Which is used to measure the air pressure?
A) Hygrometer
B) Thermometer
C) Barometer
D) Rain gauge
Answer:
C) Barometer

44. A: If roofs were weak, they could be lifted and blown away.
R: The moving air creates high pressure.
A) A & R are correct and R supports A
B) A & R are correct but R does not support A
C) A is correct but R is wrong
D) R is correct but A is wrong
Answer:
C) A is correct but R is wrong

45. Rain fall is measured with a
A) hygrometer
B) thermometer
C) barometer
D) rain gauge
Answer:
D) rain gauge

46. This is not a measuring component of weather
A) humidity
B) temperature
C) wind speed
D) none
Answer:
D) none

47. Humidity is measured in
A) g/cubic meter
B) mm/cubic meter
C) °C
D) m/°C
Answer:
A) g/cubic meter

48. In summer, the humidity of air is
A) low
B) high
C) no change
D) zero
Answer:
B) high

49. High temperatures, along with humidity sometimes may cause
A) kwashiorkor
B) beriberi
C) corona
D) sunstroke
Answer:
D) sunstroke

50. It gives the information about atmospheric conditions in a specific area and time.
A) Weather
B) Climate
C) A and B
D) None
Answer:
A) Weather

51. This deals with a long period.
A) Weather
B) Climate
C) A and B
D) None
Answer:
B) Climate

52. It affects our lifestyle
A) Weather
B) Climate
C) A and B
D) None
Answer:
B) Climate

53. Which phenomenon measures atmospheric conditions in a specific area and time?
A) Weather
B) Climate
C) A and B
D) None
Answer:
A) Weather

II. Fill in the blanks

1. Heat is a form of energy that flows from a ………………. body to a ………………. body.
2. Heat is measured in ………………. with calorimeter
3. Heat flows from a body of high temperature to a body of low temperature. This direction is determined by ………………. .
4. The degree of ………………. is called ‘temperature’.
5. Degree of Celsius is written as ………………. .
6. Degree of Fahrenheit is written as ………………. .
7. Some materials allow heat through them, this property is called ………………. .
8. Water, air, clothes, glass, cork, plastic, wood etc. are some examples of ………………. .
9. This process of transfer of heat from hotter to colder end through the conductor’ is called ………………. .
10. The contact which transfers heat by any mode is called ………………. .
11. Water is a ………………. of heat.
12. Heat is transferred by means of ………………. called convectional currents.
13. The materials which help in transfer of heat from one place to another are called ………………. .
14. Sun’s heat transfers to earth in the form of ………………. .
15. The thermal scanner receives the heat in the form of ………………. to measure our body temperature.
16. The inner ………………. in thermos flask protects the contents (tea, coffee, milk) poured in the flask from losing heat through radiation.
17. As there is ………………. between the walls of the flask; neither conduction nor convection of heat takes place.
18. Particles of substances occupies ………………. space when they get heated.
19. Small gaps left between rails in railway tracks, because metal ………………. on heat
20. ………………. are used to measure temperature.
21. The principle involved in working of a thermometer is ………………. .
22. The melting point of ice is ………………. °C
23. The melting point of ice and boiling point of water in Fahrenheit are ………………. .
24. The melting point of ice and boiling point of water in SI units are ………………. .
25. The formula to convert Celsius to Kelvin is ………………. .
26. The formula to convert Celsius to Fahrenheit is ………………. .
27. ………………. is used in hospitals to measure the temperature of the human body.
28. Clinical Thermometer has a ………………. that prevents the mercury from flowing back into the bulb when it was taken out of the patient’s mouth.
29. After taking readings in six max and min thermometer the indicators I₂ and I₁ are brought to their original places by using ………………. .
30. The normal temperature of the human body is ………………. .
31. Smoke and hot air moves up because it ………………. on heating and becomes lighter.
32. The force applied by air oh any surface in contact is called ………………. .
33. The air pressure becomes ………………. when it is compressed.
34. When air expands and raises up it creates ………………. .
35. ………………. drives the air high pressure from surrounding to move and occupy that place.
36. Air pressure is measured in height of ………………. level in centimeters
37. ………………. is measured in millimeters by using a rain gauge.
38. The water vapour present in the air is called ………………. .
39. ………………. is used to measure humidity in air and it is expressed in grams per cubic meter.
40. Evaporation of ………………. from our body makes us cool to maintain our body temperature.
41. The day-to-day variations in the components like temperature, humidity, rainfall, wind speed are called ………………. .
42. ………………. forecasting is the application of science and technology to predict the conditions of the atmosphere using components of weather for a given location and time.
43. It is easier to know about weather with the help of ………………. than tables.
44. ………………. study and work on weather and record weather every day.
45. The average weather pattern taken over a long period, say 25 years or more, is called the ………………. of the place.
46. Expansion of IMD is ………………. .
47. The abnormal variation in the components of climate is called ………………. .
Answer:

1. hotter, cooler
2. Joules or calories
3. temperature
4. hotness or coldness
5. °C
6. °F
7. conductivity
8. insulators
9. conduction
10. Thermal contact
11. poor conductor
12. currents
13. medium
14. radiation
15. radiation
16. silver coating
17. no medium or vacuum
18. more
19. expand
20. Thermometers
21. expansion of liquids on heating
22. 0
23. 32°F, 212°F
24. 273K, 373K
25. K °C + 273
26. 
27. Clinical Thermometer
28. kink
29. a magnet
30. 37°C or 98.4°F
31. expands
32. air pressure
33. more
34. low pressure
35. Low pressure
36. mercury
37. Rainfall
38. Humidity
39. Hygrometer
40. Sweat
41. weather
42. Weather
43. graphs
44. Meteorologists
45. Climate
46. Indian Meteorological Department
47. climate change

III. Match the following

1.

Answer:

2.

Answer:

3.

Answer:

4.

Answer:

5.

Answer:

6.

Answer:

7.

Answer:

Do You Know?

→ Heat is measured In Joules or Calories with calorimeter.

→ Warm air is lighter than cold air. This property of air is used in flying of hot air balloons. It contains a bag which is called as envelope, and it is filled with heated air. There is a basket under the envelope which carries passengers and a source of heat.

→ Formulas for temperature conversion

1) Celsius to Fahrenheit
2) Celsius to Kelvin C=K – 273

→ Now a days cameras have been developed to detect heat. Those are called thermal- cameras.

→ The Indian Meteorological Department (IMD) studies climate of our country. 23rd March is celebrated as World Meteorological Day.

These AP 7th Class Science Important Questions 8th Lesson Wonders of Light will help students prepare well for the exams.

AP Board 7th Class Science 8th Lesson Important Questions and Answers Wonders of Light

Question 1.
What is the source of light? Give examples.
Answer:
Light comes from different objects called sources, of light. Ex: Sun, candle, tube light.

Question 2.
What are Parallel beams of light rays?
Answer:
Light rays which travel parallel to each other are called Parallel beams of light rays.

Question 3.
What are converging beam of light, rays?
Answer:
Light rays which travel from different directions to meet at a point are called as con¬verging beam of light rays.

Question 4.
What is reflection of light?
Answer:
The process of bouncing back of light rays into the same medium after falling on a smooth or rough surface from the light source is called “reflection of light”.

Question 5.
How objects are visible?
Answer:
Objects are visible only when light falls on the objects and bounces back to the eye.

Question 6.
What is angle of incidence?
Answer:
The angle made by incident ray with the normal is called angle of incidence (i).

Question7.
What is angle of reflection?
Answer:
The angle made by the reflected ray with the normal is called the angle of reflection (r).

Question 8.
Write the first law of reflection.
Answer:
The angle of incidence is always equal to angle of reflection.
Angle of incidence = Angle of reflection
This is the first law of reflection.

Question 9.
Write the second law of reflection.
Answer:
The incident ray reflected ray and normal to the surface are present in the same plane and incident, reflected rays are on either side of normal. This is the second law of reflection.

Question 10.
How is the object distance and image distance of a plane mirror?
Answer:
The distance of the object from the mirror is equal to the distance of image from the mirror.

Question 11.
What is object distance?
Answer:
The distance of the object from the mirror is called object distance.

Question 12.
What is image distance?
Answer:
The distance of the image from the mirror is called image distance.

Question 13.
We are able to see our image in the mirror. Can we get pur image on screen?
Answer:
We cannot get the image formed by a plane mirror on the screen.

Question 14.
What is a real image?
Answer:
The image which can get on a screen is called real image.

Question 15.
What is a virtual image?
A. The image which cannot get it on screen is called virtual image.

Question 16.
How is the nature of the image formed by a plane mirror?
Answer:
The nature of the image formed by a plane mirror is virtual and erect image.

Question 17.
What is Periscope?
Answer:
Periscope is an instrument used in submarines to see the objects or persons above the water level.

Question 18.
What is the use of a Periscope?
Answer:
We can use this to see the objects outside the room through the window while hiding ourself in the room.

Question 19.
What is a convex mirror?
Answer:
The spherical mirror which has reflecting surface bent outward is called convex mirror.

Question 20.
What is a concave mirror?
Answer:
The spherical mirror which has reflecting surface bent inward is called concave mirror.

Question 21.
What is a lens?
Answer:
A piece of glass or any other transparent material with curved sides is called a lens.

Question 22.
What is a convex lens?
Answer:
Lens which is thick in center and thin at the edges is called convex lens.

Question 23.
What is a concave lens?
Answer:
Lens which is thin in the Centre and thick at the edges is called concave lens.

Question 24.
What basic principle is involved in a periscope?
Answer:
Periscope is prepared based on the principle of reflection of light from plane mirrors.

Question 25.
What are the uses of a concave mirror?
Answer:
Concave mirrors are used by dentists, ophthalmologists, ENT doctors and also in head lights of vehicles.

Question 26.
What are the uses of a convex mirror?
Answer:
Convex mirrors are used as rearview mirrors in vehicles and safety mirrors at curved roads.

Question 27.
How white light is composed?
Answer:
White light is composed of seven colours.

Question 28.
Why do dentists use a concave mirror?
Answer:
Dentists also use concave mirrors to get a bigger image of the teeth.

7th Class Science 8th Lesson Wonders of Light Short Questions and Answers

Question 1.
What is a beam of light? How many types of beam of lights are there?
Answer:
The bundle of light rays are called beam of light rays. These are three types.

1. Parallel beam of light rays
2. Converging beam of light rays
3. Diverging beam of light rays.

Question 2.
Write the differences between natural and artificial light sources.
Answer:

Question 3.
What is a ray of light? How does it represent?
Answer:

1. The direction or path along which light travels is called a ray of light.
2. It is denoted by a straight line with an arrow mark.
3. The straight line indicates the path of light and arrow mark indicates the direction of light from the source.

Question 4.
Differentiate between regular and irregular reflections.
Answer:

Question 5.
What are the characteristics of image by plane mirror?
Answer:
Characteristics of image by plane mirror:

1. Object distance is equal to image distance.
2. Size of the object is equal to size of the image.
3. The image formed is always virtual and erect.
4. Laterally inverted image is formed, (left and right alternates)

Question 6.
When you are eating food with right hand it appears to be eating with left hand in a mirror. Why?
Answer:
When you are eating food with right hand it appears to be eating with left hand in a mirror. Such a shift of lateral side of images in opposite direction is called lateral inversion. Images formed by plane mirrors undergo lateral inversion.

Question 7.
Write the differences between real and virtual images.
Answer:

Question 8.
Find the number of images will be formed, if the two mirrors are kept at an angle 50° between them?
Answer:
If the two mirrors are kept at an angle 50s between them, then the number of images between them are,

Seven is the next integer after 6.2.
So, the number of images formed will be seven

Question 9.
Write the differences between a convex mirror and a concave mirror.
Answer:

Question 10.
Write the characteristics of image formed by a concave mirror and a convex mirror.
Answer:
1) Characteristics of image formed by a concave mirror :
A concave mirror forms real and virtual images, erect and inverted images, smaller, same size and bigger images depending on the position of object infront of it.

2) Characteristics of image formed by a convex mirror :
A convex mirror always forms virtual, erect, smaller image irrespective of the position of the object.

Question 11.
How the ENT doctors are using a concave mirror?
Answer:

1. Concave mirrors are used by ENT doctors as Head mirrors.
2. They have this mirror strapped on their head.
3. Light from the bulb is made to fall on the mirror gets reflect from it.
4. This reflected light is focused into the throat or ear of the patient. So that the doctor can examine inner parts clearly.

Question 12.
How the ophthalmologists are using a concave mirror?
Answer:

1. Ophthalmologists use a special instrument called Ophthalmoscope.
2. It is fitted with a.concave mirror having a small hole near its center.
3. The concave mirror helps the doctor to direct a beam of light into the patient’s eye and see his/her retina clearly through the hole in the mirror.

Question 13.
Why the surface of reflection in a torch light or a headlight of vehicle is made with a concave mirror, behind the bulb?
Answer:

1. The surface of reflection in a torch light or a headlight of vehicle is made with a concave mirror, behind the bulb.
2. Light released from the bulb falls on the concave surface.
3. After reflection from concave surface, all the light rays travel parallel to each other.
4. So that we can observe focused light at a distance.

Question 14.
Why do convex mirrors use beside the drivers in vehicles?
Answer:

1. The convex mirrors which are used beside the drivers in vehicles are called rear view mirrors. .
2. These mirrors form images of objects spread over a large area.
3. So, these help the driver to see the traffic behind them.

Question 15.
Write the uses of convex mirrors.
Answer:

1. Large convex mirrors kept at the corners of curved roads to avoid accidents.
2. Convex mirrors form images of vehicles on both sides of curved road.
3. These mirrors are also used at the junctions of roads.
4. These mirrors used as rear view mirrors in vehicles.

Question 16.
Which colour of light is better to see? Why?
Answer:

1. Yellow light is better to see.
2. Yellow light has been proven effective in protecting retina than blue light which causes damage to retina.

Question 17.
What is the rule of 20 – 20 – 20?
Answer:
While watching TV or computer a simple rule 20 – 20 – 20 helps us in protecting eyesight. After 20 minutes of watching TV or computer screen, take 20 seconds break and watch the TV or computer around 20 feet away.

Question 18.
Akshaya got many doubts while her brother is burning a paper with a magnifier. What would be those doubts?
Answer:

1. How does a magnifier burn the paper?
2. Why are the sun rays passing through the magnifier, without reflecting back?
3. What is the shape of the magnifier?
4. What happens to the sun rays after passing through the magnifier?

Question 19.
Guess, what will happen if a concave mirror or a plane mirror is used as a rear view mirror?
Answer:

1. Generally convex mirror is used in rear view mirror.
2. Because these mirrors form images of objects spread over a large area.
3. The images’formed by the convex mirror have the characteristics like erect, virtual and smaller images.
4. So, these help the driver to see the traffic behind them.
5. If we U9e a concave mirror instead of a convex mirror it does not form any images of the rear objects.
6. If we use a plane mirror instead of a convex mirror we cannot see the images of the rear objects totally.

Question 20.
Ramesh is not able to identify different spherical mirrors. Explain him, the differ-ences between concave and convex mirrors by asking some questions.
Answer:

1. How the shining surface of the mirrors are bent?
2. What do we call the mirror, if it has reflecting surface bent inwards?
3. What do we call the mirror, if it has reflecting surface bent outwards?
4. How is your image in the both the mirrors?
5. Which mirror forms smaller image?
6. Which mirror can form your image on the wall?

Question 21.
Guess, why does we cannot see our face on a wall clearly?
Answer:
Light rays coming from the face fall on the wall and suffer irregular reflection, because wall has rough surface. Irregular reflection causes formation of no image on the wall or sometimes not cleared images.

Question 22.
How do you show the parallel light by an activity?
Answer:

1. Take a plank and cardboard.
2. Make small slits on cardboard.
3. Keep the cardboard on the plank perpendicular to it. Keep it in sunlight during afternoon.
4. The light rays from the sun fall on the cardboard and passed through the slits. We can observe that the light rays are travelling parallel to each other.

Question 23.
How do make your own spherical mirrors?
Answer:

1. Take a silver paper used for decoration.
2. Paste the silver paper without folds on a postcard size chart paper.
3. Allow it to dry by keeping it under some heavy books.
4. Bend the sheet slightly forward as its shiny surface comes inwards.
5. It works as a concave mirror.
6. Now bend the sheet slightly backward as its shiny surface comes out wards.
7. It works as a convex mirror.

Question 24.
Fill in the table with suitable answer.

Answer:

Question 25.
How do you appreciate the role of the spherical mirrors in our daily life?
Answer:

1. Concave and convex mirrors are spherical mirrors.
2. Concave mirrors are used by dentists, ophthalmologists, ENT doctors and also in head lights of vehicles.
3. Convex mirrors are used as rear view mirrors in vehicles and safety mirrors at curved roads.
4. Hence, I appreciate the role of the spherical mirrors in our daily life.

Question 26.
What precautions do you take to watch a TV?
Answer:
While watching TV or computer a simple rule 20 – 20 – 20 helps us in protecting eyesight. After 20 minutes of watching TV or computer screen, take 20 seconds break and watch the TV or computer around 20 feet away.

Question 27.
Draw the diagrams of regular reflection and diffused reflection.
Answer:

Question 28.
Draw the diagram of a source of light.
Answer:

Question 29.
Draw the diagram showing the reflection of an incident ray.
(OR)
Draw the diagram showing an incident ray, reflected ray and a normal.
Answer:

Question 30.
Draw the diagram of a periscope and lable its inner parts.
Answer:

Question 31.
Draw the diagram of a convex mirror and concave mirror.
Answer:

Question 32.
Draw the diagram of a light ray.
Answer:

Question 33.
Draw the diagrams of a convex lens and a concave lens.
Answer:

Question 34.
Draw the diagram of arrangement of the apparatus in the activity of verifi¬cation of the laws of reflection.
Answer:

7th Class Science 8th Lesson Wonders of Light Long Questions and Answers

Question 1.
a) What is reflection of light?
b) How many types of reflection are there? What are they?
c) Write the laws of reflection.
Answer:
a) The process of bouncing back of light rays into the same medium after falling on a smooth or rough surface from the light source is called “reflection of light”.

b) Reflections are of two types :
1. Regular reflection
2. Diffused reflection.

Reflection from a smooth and shiny surface is called regular reflection. Reflection from an irregular or uneven surface is called irregular reflection or diffused reflection.

c) Laws of reflection :
There are two laws of reflection.
1. Angle of incidence is equal to angle of reflection.
2. The incident ray reflected ray and normal to the surface are present in the same plane. Incident and reflected rays are on either side of normal.

Question 2.
Draw the reflected ray to the given incident ray.

Answer:

Question 3.
Answer the following.
1) What is light?
2) What is source of light?
3) How do you classify the light sources?
4) What are the different types of light beams? Explain.
Answer:
1) Light is a form of energy.

2) Light energy releases from different objects called sources of light.

3) Sources which release light energy on their own are called natural sources.
Ex: sun, stars.
Sources which need the human involvement to release light energy are called manmade sources of light.
Ex: torch light, candle, bulb etc.

4) Actually, light is not a single ray, but a bundle of rays. This bundle of light rays are called beam of light rays. These are three types :

i. Parallel beam of light rays :
Light rays which travel parallel to each other are called Parallel beam of light rays.

ii. Converging beam of light rays :
“Light rays which travel from different directions to meet at a point are called as Converging beam of light rays”.

iii. Diverging beam of light rays :
“Light rays which travel from a source moving in different’ directions are called as Diverging beam of light rays.”

Question 4.
What precautions do you take while watching TV or modern gadgets? Why?
Answer:

1. Light plays an important role in the sensation of vision.
2. Now a day’s people, due to the usage of modern gadgets, like mobile phone, com-puters, televisions through which light enters the eyes.
3. Watching TV too much or sitting very close to it may make your eyes-tired cause dryness of eyes and gradually lead to headache.
4. While using computer or TV ensures that your room is well lighted.
5. While watching TV or computer a simple rule 20 – 20 – 20 helps us in protecting eyesight.
6. After 20 minutes of watching TV or computer screen, take 20 seconds break and watch the TV or computer around 20 feet away.
7. Reduce blue light in cell phones and computers are switched on power saving mode during night.
8. Yellow light has been proven effective in protecting retina than blue light which causes damage to retina.

Question 5.
How do you appreciate the role of the reflection of light in our daily life?
Answer:

1. The process of bouncing back of light rays into the same medium after falling on a smooth or rough surface from the light source is called “reflection of light”.
2. When light falls on an object it reflects back. Reflected ray when reaches to our eyes, causes sensation of vision.
3. If there is no phenomenon of reflection, we cannot see the colourful world.
4. Periscope is prepared based, on the principle of reflection of light from plane mirrors.
5. Kaleidoscope is prepared based on the principle of multiple reflection of light from plane mirrors.
6. The dentists, ophthalmologists, ENT doctors etc. give us treatment by using reflection of light through the concave mirrors.
7. The drivers of the vehicles observe the rear objects of his vehicles by using reflection of light through the convex mirrors.
8. Hence, I appreciate the role of the reflection of light in our daily life.

AP Board 7th Class Science 8th Lesson 1 Mark Bits Questions and Answers Wonders of Light

I. Multiple Choice Questions

Choose the correct answer and write its letters in the brackets.

1. This is not a natural sources of light.
A) sun
B) stars
C) moon
D) none
Answer:
C) moon

2. Example to human involvement is needed to release light
A) sun
B) stars
C) candle
D) none
Answer:
C) candle

3. Light rays which travel from a source moving in different directions are called as of light rays.
A) parallel
B) converge
C) diverge
D) B and C
Answer:
C) diverge

4. Which of the following does not give regular reflection?
A) mirror
B) cloth
C) new steel plate
D) polished marble
Answer:
B) cloth

5. In case of irregular reflection images cure
A) not clear
B) cannot form
C) clear
D) A & B
Answer:
D) A & B

6. These are in the same plane.
i. The incident ray
ii. normal to the surface
iii. The reflected ray
A) i,ii
B) i,iii
C) ii, iii
D) i,ii,iii
Answer:
D) i,ii,iii

7. Angle between normal and the incident ray
A) angle of incidence
B) angle of reflection
C) angle of vision
D) A & B
Answer:
A) angle of incidence

8. Which of the following is not a characteristic of the image of the plane mirror?
A) Object distance is equal to image distance.
B) Size of the object is equal to size of the image.
C) The image formed is always real and erect.
D) Laterally inverted image is formed.
Answer:
C) The image formed is always real and erect.

9. The distance of the object from the mirror is …………….. the distance of image from the mirror.
A) is equal to
B) is greater than to
C) is less than to
D) A & C
Answer:
A) is equal to

10. The size of image is not equal to that of the object in any situation.
A) plane mirror
B) convex mirror
C) concave mirror
D) none
Answer:
B) convex mirror

11. The distance of the image from the mirror is called
A) Image distance
B) Object distance
C) Normal
D) None
Answer:
A) Image distance

12. This type of image can catch on the screen
A) real
B) virtual
C) both
D) none
Answer:
A) real

13. Image formed by a plane mirror
A) erect & real
B) inverted & virtual
C) erect & virtual
D) inverted & real
Answer:
C) erect & virtual

14. No. of images formed when the angle between two plane mirrors is 60°
A) 4
B) 5
C) 6
D) 7
Answer:
B) 5

15. No. of images formed when the angle between two plane mirrors is 90°
A) 4
B) 2
C) 1
D) 3
Answer:
D) 3

16. No. of images formed when the angle between two plane mirrors is 0°
A) infinity
B) 5
C) 6
D) 0
Answer:
A) infinity

17. No. of images formed is 1, then the angle between two plane mirrors is
A) 0°
B) 90°
C) 180°
D) 360°
Answer:
C) 180°

18. The instrument which is used in submarines to see the objects or persons above the water level.
A) microscope
B) telescope
C) kaleidoscope
D) periscope
Answer:
D) periscope

19. Angle between two plane mirrors in periscope is
A) 0°
B) 90°
C) 180°
D) 360°
Answer:
A) 0°

20. The steel spoon can act as …
A) plane mirror
B) convex mirror
C) concave mirror
D) B & C
Answer:
D) B & C

21. The mirror forms all types of images
A) plane mirror
B) convex mirror
C) concave mirror
D) B & C
Answer:
C) concave mirror

22. The mirror is used as rear view mirror
A) plane mirror
B) convex mirror
C) concave mirror
D) B & C
Answer:
B) convex mirror

23. Which rule we should follow to protect eyes while watching TV or computer?
A) 20-20-20
B) 40-4-40
C) 10-10-10
D) 12-12-12
Answer:
A) 20-20-20

24. Which light is not dangerous to our eye?
A) yellow
B) red
C) blue
D) violet
Answer:
A) yellow

25. Which colour of light is composition of all colours?
A) yellow
B) red
C) blue
D) white
Answer:
D) white

II. Fill in the blanks

1. Light is a form of ………………. that helps us to see all the things around us.
2. Light comes from different objects called ………………. .
3. Objects that emit light are known as ………………. .
4. Sources that release light artificially [with human involvement] are called ………………. sources of light or artificial sources of light.
5. ………………. source emit light on their own.
6. The direction or path along which light travels is called ………………. .
7. The straight line indicates the of light and arrow mark indicates the ………………. of light from the source.
8. A bundle of light rays are called ………………. of light rays.
9. Light rays which travel parallel to each other are called ………………. of light rays.
10. Light rays which travel from different directions to meet at a point are called as ………………. of light rays.
11. Light rays which travel from a source moving in different directions are called as ………………. of light rays.
12. The process of bouncing back of light rays into the same medium after falling on a smooth or rotigh surface from the light source is called ………………. .
13. Objects are visible only when ………………. falls on the objects and bounces back to the eye.
14. Light rays from the sun fall on the mirror and bounced back and formed a spot of light on the wall. It is the image of ………………. .
15. The light rays that fall on the objects are called ………………. .
16. The light rays that bounce back from the objects are called ………………. .
17. Reflection from a ………………. surface is called regular reflection.
18. Reflection from an irregular or uneven surface is called ………………. reflection.
19. Clear images are formed in case of ………………. reflection.
20. Angle of ………………. is equal to Angle of reflection.
21. Incident and reflected rays are on either side of ………………. .
22. The angle made by incident ray with the normal is called ………………. .
23. The angle made by the reflected ray with the ………………. is called the angle of reflection.
24. The distance of the object from the mirror is called ………………. .
25. The distance of the image from the is called image distance.
26. When you are eating food with right hand it appears to be eating with left hand. This characteristic is called ………………. .
27. The image which cannot catch on the screen is called ………………. .
28. Plane mirror forms ………………. image.
29. The relation between number of images formed and the angle between two plane mirrors is ………………. .
30 . ………………. is an instrument used in submarines to see the objects or persons above the water level.
31. ………………. mirror reflect the light in different directions.
32. ………………. mirror reflect the light to one point.
33. A ………………. mirror forms real and virtual images, erect and inverted images, smaller, same size and bigger images depending on the position of object infront of it.
34. Ophthalmoscope is fitted with a ………………. mirror having a small hole near its center.
35. Dentists also use ………………. mirrors to get a bigger image of the teeth.
36. ………………. mirrors are used in head lights of the vehicles.
37. A piece of glass or any other transparent material with curved sides is called ………………. .
38. Lens which is thick in center and thin at the edges is called ………………. lens.
39. Lens which is thin in the centre and thick at the edges is called ………………. lens.
40. ………………. light has been proven effective in protecting retina than blue light which causes damage to retina.
41. Splitting of white light into seven colours is called ………………. .
Answer:

1. energy
2. sources of light
3. sources of light
4. man made
5. natural
6. a ray of light
7. path, direction
8. beam
9. parallel beam
10. Converging beam
11. Diverging beam
12. reflection of light
13. Light
14. sun
15. incident rays
16. reflected rays
17. smooth and shiny
18. irregular or diffused
19. regular
20. incidence
21. normal
22. angle of incidence
23. normal
24. object distance
25. mirror
26. lateral inversion
27. virtual image
28. virtual
29. 360°/θ -1
30. periscope
31. convex
32. concave
33. concave
34. concave
35. concave
36. concave
37. a lens
38. convex
39. concave
40. Yellow
41. dispersion

III. Match the following

1.

Answer:

2.

Answer:

3.

Answer:

4.

Answer:

5.

Answer:

6.

Answer:

7.

Answer:

Do You Know?

→ We cannot see the real image with our naked eye. But we can catch it on screen. Whereas we can see the virtual image in the mirror with our naked eye. But we cannot catch it on screen.

→ In olden days the concave mirrors can also be used as weapons. Archimedes, a Greek scientist used this mirror as weapon, 2000 years ago. When the Romans attacked Syracus, a coastal City – state in Greece, Archimedes arranged concave mirrors. The mirrors could be moved in any direction. They were positioned such that they reflected the sunlight on the Roman soldiers. The soldiers were dazzled by the sunlight. They did not know what was happening. Roman soldiers got confused and returned back.

→ Convex mirrors are used in Automatic Teller Machine (ATM) for security purpose to get a wider background look. This is to avoid others from over looking at your password.

These AP 7th Class Science Important Questions 7th Lesson Reproduction in Plants will help students prepare well for the exams.

AP Board 7th Class Science 7th Lesson Important Questions and Answers Reproduction in Plants

Question 1.
What is reproduction?
Answer:
The process of giving rise to new ones of their own kind is called Reproduction.

Question 2.
What are the two types of reproduction?
Answer:
Generally, plants reproduce in two ways. They are 1) Sexual Reproduction and 2) Asexual Reproduction.

Question 3.
What is Sexual reproduction?
Answer:
Reproduction in plants with seeds is called Sexual Reproduction.

Question 4.
What is Asexual reproduction?
Answer:
Reproduction in plants without seeds is called Asexual Reproduction.

Question 5.
Give examples for plants reproduce through seeds.
Answer:
Tamarind, drumsticks, mango, neem etc. reproduce through seeds.

Question 6.
Give examples for plants reproduce without seeds.
Answer:
Jasmine, banana, rose etc. reproduce without seeds.

Question 7.
Give examples for plants reproduce by both with seeds and without seeds.
Answer:
Curry leaf, Coriander etc. can reproduce by both means.

Question 8.
Mention some asexual reproduction methods.
Answer:
Binary fission, budding, fragmentation, spore formation etc.

Question 9.
What are incomplete flowers?
Answer:
Flowers which do not have any one of the four whorls are called Incomplete flowers.

Question 10.
Give examples for complete flowers.
Answer:
Hibiscus, Datura

Question 11.
Give examples for incomplete flowers.
Answer:
Pumpkin, Ridge guard

Question 12.
What are unisexual flowers?
Answer:
In some flowers either androecium or gynoecium is present. Such type of flowers are called unisexual flowers.

Question 13.
What are bisexual flowers?
Answer:
Generally, both androecium and gynoecium are present in the same flower in most of the plants. This type of flowers are called as bisexual flowers.

Question 14.
What are male flowers?
Answer:
Unisexual flowers that contain only androecium are called male flowers.

Question 15.
What are female flowers?
Answer:
Unisexual flowers that contain only gynoecium are called female flower.

Question 16.
What is the third whorl of a flower?
Answer:
The third whorl of a flower is androecium. This is the male reproductive part of the flower.

Question 17.
What is the 4th whorl of a flower?
Answer:
The fourth whorl of a flower is gynoecium. This is the female reproductive part of the flower.

Question 18.
What are the reproductive parts of a flower?
Answer:
Androecium and Gynoecium are the reproductive parts of a flower.

Question 19.
What is pollination?
Answer:
The process of transferring pollen grains from anther to stigma is called as Pollination.

Question 20.
What is self-pollination?
Answer:
If the pollen grains are transferred from the anther of a flower to stigma of the same flower, is known as SELF POLLINATION.

Question 21.
What is cross pollination?
Answer:
If the transfer of pollen grains takes place from the anther of one flower to the stigma of another flower, it is called CROSS POLLINATION.

Question 22.
Mention some pollinating agents.
Answer:
Insects, birds, animals, air and water are the pollinating agents.

Question 23.
Why do plants try to spread their seeds to distant places?
Answer:
All the plants try to spread their seeds to distant places to increase the chance of survival and propagation.

7th Class Science 7th Lesson Reproduction in Plants Short Questions and Answers

Question 1.
What is reproduction? How is it useful to the plants?
Answer:

1. The process of giving rise to new ones of their own kind is called Reproduction.
2. Reproduction helps to increase their number and continue their existence.
3. All plants produce new once like them.
4. There is no existence for plants without reproduction.

Question 2.
Write the differences between sexual and asexual reproductions in plants.
Answer:

Question 3.
Write the differences between calyx and corolla.
Answer:

Question 4.
Write the differences between bisexual flowers and unisexual flowers?
Answer:

Question 5.
Differentiate male and female flowers.
Answer:

1. Unisexual flowers that contain only androecium are called male flowers.
2. Unisexual flowers that contain only gynoecium are called female flowers.

Question 6.
How can you identify a female flower?
Answer:

1. Female flowers are not difficult to identify.
2. Notice the flowers on the variety of gourd creepers we grow around our home.
3. Commonly below the petals of the flower are just a stalk found in the male flowers, while in the female flowers, a small berry-like form is seen below the flower which is ready to bear fruit in further days.
4. By observing the presence of that berry-like form, we can identify the female flowers.

Question 7.
Write the differences between self-pollination and cross pollination.
Answer:

Question 8.
How do insects and some birds help in pollination?
Answer:

1. Insects like butterflies, honeybees, bumble bees, humming birds, bats, ants visit the flowers in search of nectar.
2. When insects come in contact with a flower, the pollen grains stick to their legs and wings.
3. When insects visit another flower, the pollen fall on its slimy stigma.
4. Thus they help in pollination.

Question 9.
How do fertilization takes place in plants?
Answer:

1. The pollen grains which fall on the stigma of a flower germinates.
2. A pollen tube is formed from the pollen grains.
3. The pollen tube travels from stigma to the ovules in the ovary.
4. Fertilization and zygote formation occur in ovary.
5. The zygote develops into an embryo.

Question 10.
What changes will come in the flower after fertilization?
Answer:

1. After fertilization the ovary ripens and turns into fruit.
2. The remaining floral parts will fall off.
3. The ovules become the seeds.

Question 11.
What is seed dispersal? Mention different means of seed dispersal.
Answer:

1. Spreading of seeds from one place to another place is called seed dispersal.
2. Seed dispersal may happen through wind, water, animals, birds, man and even through some mechanical processes such as bursting of fruits.

7th Class Science 7th Lesson Reproduction in Plants Long Questions and Answers

Question 1.
What is vegetative propagation? Mention different vegetative propagation methods and their examples.
Answer:
Reproduction in plants through vegetative parts such as stem, root, and leaves is called vegetative propagation.

Question 2.
Explain the process of ground layering.
Answer:

Ground Layering

1. Layering is done with branches nearer to the ground.
2. Remove the bark of the stem at one place.
3. Bend the branch into the ground and cover it with soil.
4. Within one month roots will develop from that branch.
5. Separate it from the mother plant and plant it where ever you want.
6. This method is useful to propagate Jasmine, Jaji, Bougainvillea, Strawberry etc. Plants with creeping stem.

Question 3.
What is grafting? Explain the method of grafting.
Answer:
Grafting is a technique where two plants are joined so as to continue their growth together. The upper part of the combined plant is called the scion, while the lower part is called the stock.

Procedure:

1. Remove the bark of the Stock and Scion plants in such a way that removed portions face each other.
2. The parts where bark is removed are joined tightly with the help of a jute twine.
3. Wrap and tie with a polythene paper.
4. After a month, cut the upper part of Stock and lower part in Scion.
5. Within an another month the Scion attaches to the Stock and grows.
6. Now remove the new branches which grow on Stock to facilitate the growth of Scion.

Question 4.
Describe the structure of a flower.
Answer:
Flower is the sexual part of a plant. The green part which connects the flower to stem is called the stalk. The stalk bears a slightly swollen head called Thalamus.

Over the thalamus floral parts are arranged in four whorls.

Calyx:
The green cup shaped leaf like, fused structures that covers the internal parts are Sepals. They are collectively called as Calyx. (Whorl 1)

Corolla:
The white or brightly coloured structures are called Petals. They are collec¬tively called as Corolla. (Whorl 2) .

Androecium:
The soft elongated structures attached to the petals are called Stamens. All the stamens are collectively called Androecium (Whorl 3). This is the male reproductive part of the flower. Each stamen has a swollen structure at the top called Anther.

Gynoecium:
A bulged structure seated on the thalamus is called Ovary which continues into a fine tube like structure Style with a slimy bead like tip called Stigma. These are collectively called the pistil Gynoecium (Whorl 4). This is the female reproductive part of the flower’

Question 5.
Write the differences between Androecium and Gynoecium.
Answer:

Question 6.
Draw the different whorls of a flower.
Answer:

Question 7.
Do you find any relationship between the weight of the seeds and the dispersal mechanism? Discuss with suitable examples.
Answer:

1. I find relationship between the weight of the seeds and the dispersal mechanism.
2. For example : Seeds of calotropis.
   a) These are light and have hairy structure at one end.
   b) So they travel with wind and settle at a suitable place to germinate.
   c) Milk weed, cotton seeds, etc. are all dispersed by wind.
3. Another example : Coconut fruit
4. a) The outer covering of the seed has empty spaces filled with air and are fibrous,
   b) The coconut fruit floats on water and reaches the ground some where. There it germinates. Seeds of lotus is another example.
5. Another example : Neem fruit.
   a) Birds like Bulbuls, Mynahs, crows eat the outer fleshy part gets digested in the food canal and the seed coats of them become tender.
   b) They are then dispersed to other places as bird droppings.
6. Similarly animals, Human beings carry the seeds to other places.

AP Board 7th Class Science 7th Lesson 1 Mark Bits Questions and Answers Reproduction in Plants

I. Multiple Choice Questions

Choose the correct answer and write its letters in the brackets.

1. Seeds are related to
A) stem
B) root
C) flower
D) leaf
Answer:
C) flower

2. Sugarcane propagates through
A) nodes
B) leaf
C) root
D)suckers
Answer:
A) nodes

3. Ground layering is seen in
A) Jasmine
B) Bougainvillea
C) Strawberry
D) All
Answer:
D) All

4. Which one is formed from layering branch?
A) Roots
B) Leaves
C) Nodes
D) Fruits
Answer:
A) Roots

5. The rooted plant in grafting is called as
A) Scion
B) Stock
C) Node
D) Cutting
Answer:
B) Stock

6. In grafting which have desirable characters
A) Scion
B) Stock
C) Root
D) Leaf
AnsA) Scionwer:

7. This symbol represents
A) Female
B) Male
C) Both
D) Flower
Answer:
B) Male

8. This symbol represents
A) Male
B) Female
C) Both
D) Pollination
Answer:
B) Female

9. This diagram indicates
A) Pistil
B) Corolla
C) Stamens
D) Sepals
Answer:
A) Pistil

10. How many whorls that the complete flower has
A) 2
B) 3
C) 4
D) 5
Answer:
C) 4

11. Complete flowers also called as
A) Male flower
B) Female flower
C) Unisexual flower
D) Bisexual flower
Answer:
D) Bisexual flower

12. Ipomea have
A) Unisexual flower
B) Bisexual flower
C) Male flower
D) Female flower
Answer:
B) Bisexual flower

13. The zygote develops into
A) Embryo
B) Fruit
C) Flower
D) Stem
Answer:
A) Embryo

14. Which of the flower colour change after fertilization?
A) Mango
B) Rose
C) Cotton
D) Neam
Answer:
C) Cotton

15. Seeds compitect for
A) Soil
B) water
C) light
D) All
Answer:
D) All

16. Which process makes life immortal?
A) Reproduction
B) Digesion
C) Respiration
D) Circulation
Answer:
A) Reproduction

17. Transfer of pollen to stigma is
A) Pollination
B) Fertilization
C) Germination
D) Growth
Answer:
A) Pollination

18. Assertion (A) : A stamen has 2 parts.
Reason (R) : Filament and anther are parts of a stamen.
A) Both ’A’ and R’ are true and R’ is the correct explanation of ‘A’.
B) Both A’ and ‘R’ are true but ‘R’ is not the correct explanation of ‘A‘.
C) ‘A’ is true but R’ is false.
D) A’ is false but ‘R’ is true.
Answer:
A) Both ’A’ and R’ are true and R’ is the correct explanation of ‘A’.

19. Assertion (A) : Parts of pistil are anther and filament.
Reason (R) : Bisexual flowers are those which contain both stamen ahd pistil.
A) Both ‘A’ and ‘R’ are true and ‘R’ is the correct explanation of ‘A’.
B) Both ‘A’ and ‘R’ are true but ‘R’ is. not the correct explanation of ‘A’.
C) ‘A’ is true but ‘R’ is false.
D) ‘A’ is false but ‘R’ is true.
Answer:
D) ‘A’ is false but ‘R’ is true.

20. Assertion (A) : A flower may either have a male or a female part.
Reason (R) : A flower having both male and female parts is called bisexual flower.
A) Both A’ and ‘R’ are true and ‘R’ is the correct explanation of ‘A’.
B) Both ‘A’ and ‘R’ are true but ‘R’ is not the correct explanation of ‘A’.
C) ‘A’ is true but ‘R’ is false.
D) ‘A’ is false but ‘R’ is true.
Answer:
B) Both ‘A’ and ‘R’ are true but ‘R’ is not the correct explanation of ‘A’.

21. Statement (I): After fertilization the ovary becomes the fruit and ovules the seeds.
Statement (ii) : Study of pollen grains is called polynology.
A) Statement (i) is correct while statement (ii) is incorrect.
B) Statement (ii is correct while statement (i) is correct.
C) Both statements are correct.
D) Both statements are incorrect.
Answer:
C) Both statements are correct.

22. It is the seat on which the parts of a flower are present.
A) Corolla
B) Thalamus
C) Calyx
D) Androecium
Answer:
B) Thalamus

23. It has funnel shape.
A) Corolla
B) Sepals
C) Calyx
D) Thalamus
Answer:
A) Corolla

24. This is the male part of the flower.
A) Gynoecium
B) Androecium
C) Petals
D) Sepals
Answer:
B) Androecium

25. This is the female part of a flower.
A) Petals
B) Calyx
C) Gynoecium
D) Androecium
Answer:
C) Gynoecium

26. An example for unisexual flower.
A) Bittergourd
B) Datura
C) Ipomea
D) Hibiscus
Answer:
A) Bittergourd

27. This is a bisexual flower.
A) Papaya
B) Cucumber
C) Bottlegourd
D) Hibiscus
Answer:
D) Hibiscus

28. The fleshy base to which all the floral parts are attached to is
A) Pedicel
B) Sepals
C) Thalamus
D) Petals
Answer:
C) Thalamus

29. The pollen grains are found in
A) Ovule
B) Anthers
C) Ovary
D) Stigma
Answer:
B) Anthers

30. The number of stamens present in Datura :
A) 5
B) 3
C) 6
D) 10
Answer:
A) 5

31. Ovules develop into :
A) flowers
B) plants
C) leaf
D) seeds
Answer:
D) seeds

32. The pollen grains contain
A) male garnets
B) female garnets
C) filaments
D) Stigma
Answer:
A) male garnets

33. It is a ……………
A) Unisexual flower
B) Bisexual flower
C) Female flower
D) Male flower
Answer:
C) Female flower

34. In which type of flower this part is present?
A) Male flower
B) Bisexual flower
C) Both A & B
D) None of these
Answer:
C) Both A & B

35. Identify the part of flower
A) Stamen
B) Pistil
C) Petals
D) Sepals
Answer:
A) Stamen

36. Identify the part of flower.
A) Stamen
B) Pistil
C) Petals
D) Sepals
Answer:
B) Pistil

37. It shows that
A) T.S of flower
B) L.S of flower
C) T.S of stem
D) T.S of root
Answer:
B) L.S of flower

38. Pollen grains are formed from
A) Stamen
B) Pistil
C) Ovary
D) Sepals
Answer:
A) Stamen

39. In the pollination what is transfer from anther to stigma?
A) Ovule
B) Zygote
C) Seed
D) Pollengrain
Answer:
D) Pollengrain

40. Agents of pollination
A) Birds
B)Insects
C) Air
D) All of these
Answer:
D) All of these

41. New plants grow from the following part of a plant is not a vegetative reproduction
A) Root
B) Stem
C) Leaf
D) Flower
Answer:
D) Flower

42. This develops as fruit.
A) Ovary
B) Ovule
C) Petals
D) Flower
Answer:
A) Ovary

43. Ovules develop into
A) fruit
B) seed
C) flower
D) plant
Answer:
B) seed

44. Dispersal of this seed is by water.
A) Coconut
B) Soap nut
C) Neem
D) Milk weed
Answer:
A) Coconut

45. Dispersal of calotropis is through
A) Water
B) Animals
C) Wind
D) Humans
Answer:
C) Wind

46. These seeds are dispersed by animals.
A) Fleshy fruits
B) Coconut
C) Neem
D) Balsam
Answer:
A) Fleshy fruits

47. Neem seed is dispersed to other places by
A) Animals
B) Human beings
C) Birds
D) Water
Answer:
C) Birds

48. Dispersal by bursting of these fruits is done.
A) Neem
B) Coconut
C) Fleshy fruits
D) Bhendi
Answer:
D) Bhendi

49. People transferred these seeds across the globe.
A) Coconut
B) Neem
C) Soap nut
D) Sugarcane
Answer:
D) Sugarcane

50. Among the following dispersal of seed occurs through wind in
A) Coconut
B) Lotus
C) Milkweed
D) Mango
Answer:
C) Milkweed

51. Seeds of Lotus travel by
A) Birds
B) Insects
C) Animals
D) Water
Answer:
D) Water

52. These are carried by birds
A) Maple
B) Milkweed
C) Lotus
D) Neem
Answer:
D) Neem

53. On drying the pod explodes releases seeds with great force in
A) Mustard
B) Sugarcane
C) Pears
D) Tomato
Answer:
A) Mustard

54. These seeds are dispersal through
A) Water
B) Wind
C) Animals
D) Birds
Answer:
B) Wind

55. These seeds are dispersal through
A) Wind
B) Water
C) Animals
D) Birds
Answer:
B) Water

56. Seeds of sweet and fleshy fruits can dispersal through
A) Human beings
B) Birds
C) Animals
D) All of these
Answer:
C) Animals

57. Seed dispersal is essential for survival of
A) Plants
B) Animals
C) Birds
D) Human beings
Answer:
A) Plants

58. Cotton seeds have the following structures
A) Wing like outer growths
B) Hooks
C) Hairy parts
D) Thorns
Answer:
C) Hairy parts

59. The following seeds dispersal through human beings
A) Bhendi
B) Coconut
C) Tomato
D) Cotton
Answer:
C) Tomato

60. Identify the wrong statement.
A) All the seeds of a fruit should be able to germinate
B) Some seeds germinate but plants die before maturation
C) Some seeds never germinate
D) All seeds do not germinate
Answer:
A) All the seeds of a fruit should be able to germinate

61. This seed is dispersed by
A) Water
B) Air
C) Animals
D) Bursting
Answer:
C) Animals

62. Dispersal of seeds by bursting of fruits happens in
A) Sugarcane
B) Coconut
C) Lotus
D) Ladies finger
Answer:
D) Ladies finger

II. Fill in the blanks.

1. The propagation of Banana is through ………………………. .
2. The propagation of sugarcane is done by planting ………………………. .
3. Mint is propagated through ………………………. .
4. In potatoes, ………………………. are used for propagation.
5. In onions ………………………. are used for propagation.
6. Example for rhizome is ………………………. .
7. Example for corm is ………………………. .
8. Example for stem cutting is ………………………. .
9. Examples for ground layering are ………………………. .
10. Artificial propagation method used for getting plants with desired characters is ………………………. .
11. Sepals of a flower collectively called as ………………………. .
12. Petals of a flower are are collectively known as ………………………. .
13. Calyx is present in ………………………. whorl.
14. Corolla is present in ………………………. whori.
15. The male reproductive part of the flower is ………………………. .
16. The female reproductive part of the flower is ………………………. .
17. Androecium consists of ………………………. .
18. Gynoecium consists of ………………………. .
19. Androecium is present in ………………………. whorl of the flower.
20. Gynoecium is present in ………………………. whorl of the flower.
21. The smooth yellow coloured powder in anther is called ………………………. .
22. Transferring pollen from anther to stigma of the same flower is
23. Transferring of pollen grains from anther of one flower to stigma of another flower is known as ……………….. .
24. When pollen grains fall on stigma is ………………………. formed.
25. The fusion of pollen grains with ovules in ovary is known as ………………………. .
26. Fertilization results in the formation of ………………………. .
27. After fertilization, ovary ripes and turn into a ………………………. .
28. After fertilization, ovules turn into ………………………. .
29. Seeds with wings are carried away by ………………………. .
30. Example for seed dispersal through water is ………………………. .
31. Seeds of calotropis dispersed with the help of ………………………. .
32. Seeds of fleshy fruits are dispersed through ………………………. .
33. Seeds having hooks are dispersed with the help of ………………………. .
34. Neem seeds are dispersed with the help of ………………………. .
35. Seeds having hairs dispersed through ………………………. .
36. Dispersal of seed take place by bursting of fruits can be seen in ………………………. .
37. Lotus seeds are dispersed through ………………………. .
38. In Mustard, seeds dispersal takes place through ………………………. .
39. Seeds dispersed through aeroplanes and ships are ………………………. .
40. Flower shown in the picture is ………………………. .
41. Grafting technique is used in the plants like ………………………. for getting desired characters.
Answer:

1. suckers
2. nodes of sugarcane
3. cut the twigs with nodes and sow them
4. eyes
5. Bulb
6. Ginger
7. colocasia
8. rose
9. Jasmine, Jaji
10. grafting
11. Calyx
12. Corolla
13. 1st
14. 2nd
15. Androecium
16. Gynoecium
17. Stamens
18. Ovary with style and stigma
19. 3rd
20. 4th
21. pollen grains
22. Self – pollination
23. cross – pollination
24. pollen tube
25. fertilization
26. zygote
27. fruit
28. seeds
29. wind
30. coconut, louts
31. wind
32. animals, birds and man
33. animals
34. birds
35. wind
36. bhendi, balsam
37. water
38. bursting mechanism
39. pulses, wheat, paddy
40. Unisexual flower (or) incomplete flower
41. mango, guava etc.

III. Match the following

1.

Answer:

2.

Answer:

3.

Answer:

4.

Answer:

5.

Answer:

6.

Answer:

Do You Know?

→ You will be amazed that banana contains seeds. The rose plant also has red fruits with seeds. Do you know that Nandivardhanam and Hibiscus also have seeds* There are nuts and seeds in the rose and banana plants that grow wild without human interference in forests. The rose and banana plants that are found in our surroundings have no seeds. Do you know the reason? Our ancestors grew these plants with seeds of the plants with seeds of the plants that were found in the forest.

With the efforts made over many generations to propagate them as plants with favourable characteristics, they became seedless plants.

→ Can you imagine a single plant giving 40 types of fruits such as peaches, apricots, plums, cherries, nectarines and so on? Such types of plants can be produced by Grafting.

These AP 7th Class Science Important Questions 6th Lesson Electricity will help students prepare well for the exams.

AP Board 7th Class Science 6th Lesson Important Questions and Answers Electricity

Question 1.
How does a bulb glow?
Answer:
When we switched ON the bulb, electricity flows through the wire and makes the bulb glow.

Question 2.
What is a cell?
Answer:
A cell is a device used to generate electricity.

Question 3.
What are the anpde and cathode in a cell?
Answer:

1. Anode and cathode are the two electrodes in a cell.
2. The positive electrode is called anode and the negative electrode is called cathode.

Question 4.
What is the electrolyte in a cell?
Answer:
The electrolyte is a chemical component that conducts the electricity.

Question 5.
Which parts of the battery function as an anode and a cathode?
Answer:

1. The container which is made of zinc metal works as the cathode (negative terminal).
2. A carbon rod with a metal cap works as an anode (positive terminal).

Question 6.
Name the common chemicals present in the dry cell.
Answer:

1. Carbon powder
2. Ammonium chloride.

Question 7.
What Is a battery?
Answer:
A group of cells Is called a battery.

Question 8.
Write different types of cells.
Answer:
1) Dry cell, 2) Lithium cell, 3) Button ceils, 4)Alkaline cell

Question 9.
Write one difference between fuse and MCB.
Answer:
There is no need to change the fuse wire in MCB. But fuse wire has to be changed whenever it melts in fuse device.

Question 10.
What precantion do you take while connecting copper wire in the circuit?
Answer:
While connecting copper wire in the circuit, the copper coating at the two ends erf the copper wire should be cleaned or scratched.

Question 11.
What is a simple electric circuit?
Answer:
A simple electric circuit consisting of a battery, a bulb, a switch, and connecting wires.

Question 12.
What are circuit diagrams?
Answer:
The diagrams which show the arrangement of electric components in a circuit are called circuit diagrams.

Question 13.
Write the common sequence of components in electric circuit diagram.
Answer:
Positive terminal of the cell → wire → bulb → wire → switch → wire → negative terminal of the cell.

Question 14.
What is the tearing effect of electricity?
Answer:
The production of heat due to the flow of electricity through a wire is called heating effect of electricity.

Question 15.
Name the metal used as a filament in the iron box and buld?
Answer:

1. Generally, the filament in an iron box is made up of Niehrome.
2. The filament in a bulb is made of Tungsten.

Question 16.
What is magnetic effect of electricity?
Answer:
The production of magnetic force due to the flow of electricity thrombi a wire is called Magnetic effect of electricity.

Question 17.
What are electromagnets?
Answer:
The devices which act as magnets when electricity passes through them are called electromagnets.

Question18.
On what principle do electric cranes work?
Answer:
Electric cranes are worked on the principle of magnetic effects of electricity.

Question 19.
Answer:

1. By using repulsion property of a magpet, a magnetic object can levitate.
2. Electromagnetic train runs on this principle.

Question 20.
How does electricity bill calculated?
Answer:
Generally, electricity bills are calculated on the basis of number of units of electricity consumed.

Question 21.
What is wattage of a bulb? What does it mean?
Answer:

1. 1) The wattage measures how powerful the electric device is.
2. The brighter the bulb, the higher its wattage and more the electricity used by it.

Question 22.
What is meant by KWH?
Answer:

1. Wiser? I kilo watt is used per one hour, it Is considered as 1 kilo watt hour (KWH)
2. 1 KWH = 1 UNIT of electricity.

Question 23.
What is the unit of electricity consumption?
Answer:
Kilo watt hour (or) UNIT.

Question 24.
From where electricity soppiied to owr booses?
Answer:
Electricity supplied to our houses comes ban the power stations and substations.

Question 25.
Where do we use lithium-ion cells and why?
Answer:
Lithium ion cells are rechargeable and are used in mobile phones, laptops etc.

Question 26.
Where do we use button cells?
Answer:
Button cells are used in wrist watches, laser lights. thermometers (electronic), computers etc.

Question 27.
Where is the use of a switch?
Answer:
Switch is used to open or dose a circuit.

Question 28.
Write different types of Im21» which areasedht omr daily life.
Answer:
In our daily life we use different types of bulbs. Some of them are Incandescent bulb, fluorescent both (tube light). CFL (Compact Fluorescent Lamp), LED bulb etc.

Question 29.
What is the use of parallel connection of cells in a circuit?
Answer:
The parallel connection of cells, increases the battery life.

Question 30.
Guess, what happens if one of bulbs is burnt in a series connection?
Answer:
It one of the bulbs is burnt, remaining bulbs also not glow because of circuit is opened.

Question 31.
What are the material required to make a cell with lemons?
Answer:
Zinc plate, copper plate, a small bulb, or LED, connecting wires, crocodile dips, and lemons.

Question 32.
Where do you find series and parallel connections of bulbs in your real life?
Answer:

1. Parallel connections of bulbs are found in houseshold connections.
2. Series connections of bulbs are found in decorative purpose connections.

Question 33.
What are the risks of electric shock?
Answer:
Explosure to electricity may result in no injury at all or may result in major damage or sometimes lead to death also.

7th Class Science 6th Lesson Electricity Short Questions and Answers

Question 1.
Answer:

1. A cell is device used to generate electricity.
2. It contains two elect rides and a chemical.
3. When electrodes come in contact with electrolyte, a chemical reaction takes place inside the cell to produce electricity.
4. It converts the chemical energy into electrical energy.
5. When electrodes and connected to the wires in a circuit, electricity passes through them.

Question 2.
What are the main components of a cell? Explain.
Answer:

1. A cell is a device used to generate electricity.
2. It mainly consists of two components.
   i) Electrolyte : This is a chemical component that conducts the electricity.
   ii) Electrodes : There are two electrodes in a cell. One is positive electrode called anode and the other is negative electrode called cathode.

Question 3.
Why and how do we save electricity?
Answer:

1. Our country faces shortage of electricity.
2. So, we should use electricity careful! and only when it is needed.

Question 4.
How long a dry cell works?
Answer:

1. The cell can supply electricity in a circuit for a period of time.
2. After that, chemicals present in it get exhausted and it cannot produce electricity.

Question 5.
Why should we replace an ordihary bulb with a LED bulb?
Answer:

1. The ordinary bulb we use gives us light and also heat.
2. This is not desirable.
3. This results in the wastage of electricity.
4. Hence, we should replace an ordinary bulb with a LED bulb.
5. LED bulbs consume less electricity than ordinary bulb.

Question 6.
How do you find an electrical device which consumers less electricity?
Answer:

1. Now-a-day every electrical device is marked with a power saving guide which contains star symbols.
2. The number of stars on them indicates the energy efficiency of that device.
3. The electrical appliance with more stars consumes less electricity.
4. Hence, it is advised to select electrical appliances with more stars.

Question 7.
How does an electric fuse protect home appliances?
(OR)
How do you appreciate the electric fuse?
Answer:

1. Electric appliances may get damaged when excess of electricity flows through them.
2. To protect them from such accidents, a safety device called electric fuse is used.
3. Electric fuse has a body made of ceramic.
4. It has two points for connecting the fuse wire.
5. If there is an overload of electricity in the circuit, the fuse wire melts because of low melting point.
6. This breaks the circuit and helps in preventing damage to electrical appliances.

Question 8.
How does a MCB work?
(OR)
How do you appreciate the role of MCB in the protection of electrical home appliances?
Answer:

1. MCB means Miniature Circuit Breaker.
2. It is being used in place of electric fuses.
3. There is a switch which automatically turns off when electricity in circuit exceeds the safe limit.
4. So, the circuit is opened.
5. We just need to switch ON to resume electric supply.
6. At present MCB is available with automatically resumed built-in mechanism.
7. MCB is better than electric fuses.
8. There is no need to change it often.
9. But fuse wire has to be changed whenever it melts.
10. Hence, I appreciate the MCB for protecting home appliances.

Question 9.
What is series connection of devices? What happens if any one of the devices is removed?
Answer:

1. If the second terminal of the first device is connected to the first end of the second device, such type of connection is called series connection.
2. In series connection electricity has only one path.
3. If any of them is removed or not functioning properly, it becomes an open circuit.

Question 10.
What is parallel connection of devices ? What is its advantage?
Answer:

1. If all the first terminals of all the devices are connected to one point and all the second terminals are connected to another point such type of connection is called parallel connection.
2. In parallel connection electricity has more than one path.
3. Even if any one of them is removed the circuit remains closed.

Question 11.
How does the brightness of the bulb changes, if a number of cells are connected 0 in series ii) in parallel?
Answer:
i) If a number of cells are connected in series the brightness of the bulb is enhanced,
ii) If a number of cells are connected in parallel the brightness of the bulb remains same (or) does not change.

Question 12.
Why the batteries in a torch light are connected in series?
Answer:

1. If we connect batteries/cells in series it enhance the brightness of the bulb, the batteries in a torch light are connected in series.
2. So, to enhance the brightness of the bulb.

Question 13.
How does the brightness of the bulb change when a number of bulbs are connected in i) series ii) parallel?
Answer:
i) If a number of bulbs are connected in series the brightness of the bulb is reduced.

ii) If the number of bulbs are connected in parallel, the brightness of the bulb remains same.

Question 14.
How does an electric-iron box work?
Answer:

1. The electric iron box contain a coil of wire, which is generally made up of Nichrofne.
2. This coil of wire is called a filament, which produce heat, when current is passed through it.

Question 15.
How does a bulb with filament glow?
Answer:

1. When electric current is passed through the filament (made with Tungsten), it becomes red hot and further becomes bright white.
2. This bright white glow of the filament gives light.

Question 16.
What happens if we pass current through the copper coil around a nail?
Answer:
The nail acts as a magnet, when current is passed through the coil around it.

Question 17.
Are electro-magnets permanent magnets? Justify your answer.
Answer:

1. Electromagnets are not permanent magnets.
2. Because, they lose the property of magnetism when the circuit is open.

Question 18.
Write some situations which lead to an electric shock.
Answer:

1. Operating a switch with a wet hand.
2. Removing plug pins when the switch is on.
3. Using wires without insulation.
4. Changing bulb when the switch is on.
5. Holding a person with a current shock.

Question 19.
What immediate action should we take to save a person who gets electric shock?
Answer:

1. When anybody gets an electric shock.
2. First, cut off the power supply.
3. If it is not possible, push away the person with a dry stick.
4. If the shock is severe and the person is unconscious, give mouth to mouth artificial respiration.
5. Sometimes heart beat ceases, at that time keep your palms on his chest and press down and release until the heartbeat is recovered. This is called Cardio Pulmonary Resuscitation (CPR). Immediately take him to the hospital.

Question 20.
What is ISI? What is its use?
Answer:

1. ISI means Indian Standards Institution.
2. It can be observed on the electrical devices.
3. The ISI mark ensures the quality of appliances and safety of users.

Question 21.
When the power to house cut off, the Saritha noticed that her father was changing the fuse wire. Then she had many doubts. What would be those doubts?
Answer:

1. What is fuse?
2. How does it work?
3. What happens to the fuse, when current is cut off?
4. What is the use of fuse?

Question 22.
Filament bulbs are hot, but some other bulbs like LED, CFL are cold. Guess, what is the reason?
Answer:

1. Filament bulbs are made up of Tungsten filaments.
2. These are working on the principle of heating effect of the electricity.
3. So, they are hot.
4. But, other bulbs like CFL and LED are not working on this principle. Hence they are cool.

Question 23.
Guess, what would happen if home appliances were connected in a series connection?
Answer:

1. If one device is stopped or failed to work, all other devices will also stop.
2. If one device is switched on the other devices will also works.

Question 24.
Write the procedure of making of our own cell.
Answer:

1. Take a lemon and insert a zinc plate and a copper plate into it.
2. These plates acts as electrodes and the juice inside the fruit acts as electrolyte.
3. Connect two terminals of the bulb to zinc and copper plates using connecting wires.
4. The bulb will glow.

Question 25.
Write the required materials to do an activity to know about heating effect of electric current.
Answer:

1. Electric cell,
2. Iron nails – 2,
3. Wooden board,
4. Connecting wires,
5. 10 cm of Nichrome wire etc.

Question 26.
Write the material required to make a electromagnet.
Answer:
Battery, Switch, Iron nail, Insulated copper wire, and small pins.

Question 27.
What happens if the switch is open in the experiment of given picture.

Answer:
When we switched off the circuit, immediately all the pins fall from the iron nail.

Question 28.
Observe the diagram and write answers to the given questions.

1) Which bulb is more power saver?
2) Which bulb has less life span?
3) Which bulb do you suggest for your home?
4) Which bulb works on the principle of heating effect of electricity?
Answer:

1. LED
2. Incandescent
3. LED
4. Incandescent.

Question 29.
Fill in the table with suitable answers.

Answer:

Question 30.
Observe the following circuit diagrams and answer the question.

What difference do you find between diagrams A and B?
Answer:
We observe that the bulb in circuit A is not glowing and in circuit B it is glowing.

We can also see the switch is in OFF mode in circuit diagram A and it is in ON mode in circuit diagram B. Circuit diagram A represents open circuit, where as circuit diagram B represents closed circuit.

Question 31.
Observe the figure and give answers to the questions.
1) How are the cells connected?
2) If one of the cells is disconnected what will happen?

Answer:

1. Cells are connected in parallel.
2. The bulb will glow as usual if one of the cells is disconnected.

Question 32.
Draw the given diagram by using symbols instead of realistic components.
Answer:

Question 33.
Draw the diagram of setup of material in make a cell with lemon.
Answer:

Question 34.
Draw the diagram of a simple circuit.
Answer:

Question 35.
Draw a circuit diagram showing the parallel connection of the cells.
Answer:

Question 36.
Draw a circuit diagram showing the series connection of the cells.
Answer:

37. Draw a circuit diagram showing the parallel connection of bulbs.
Answer:

38. Draw a circuit diagram showing the series connection of bulbs.
Answer:

39. Draw a device alignment diagram of equipment in the experiment of heating effect of electric current.
Answer:

40. Draw the diagram showing the arrangement of circuit to make an electromagnet.
Answer:

41. Draw the symbol of ISI mark.
Answer:

42. Where do we use dry cells? What are its advantages?
Answer:

1. In our daily life we use dry cells in torch lights, wall clocks, radios etc.
2. Dry cell consists of an electrolyte in dried form.
3. So, it is easy to move anywhere.

Question 43.
How does a switch work in a circuit?
Answer:

1. We know that switch Is used to open or dose a circuit
2. When the switch is ‘off’ position, bulb does not glow, because the circuit Is opened.
3. If we keep the switch in ‘on’ mode, the circuit is closed and the bulb glows.

Question 44.
How do circuit diagrams help to electricians?
Answer:

1. A circuit diagrams is a graphic representation of an electric circuit
2. It shows how the electric components are connected together.
3. Electricians and engineers draw circuit diagrams to help them design the actual circuits.

Question 45.
What is the first aM few electric shock?
(OR)
How do you perform CPR?
Answer:

1. It the electric shock is severe and the person is unconscious, given mouth to mouth artificial respiration.
2. Sometimes heartbeat ceases, at that time keep your palms on his chest and press down and release until the heartbeat is recovered, this is called Cardio Pulmonary Resuscitalion (CPR)

Question 46.
How do you check for the good electric appliances?
Answer:
While selecting electric appliances:

1. Check ISI (Indian Standard institution) mark on all electrical appliances before you buy.
2. Check for more star rating.

7th Class Science 6th Lesson Electricity Long Questions and Answers

Question 1.
What is a cell? How does it work?
Answer:
A cell is a device used to generate electricity. It mainly consists of two components.

1. Electrolyte – This is a chemical component that conducts the electricity.
2. Electrodes – There are two electrodes in a ceiL One is positive electrode called anode and the other is negative electrode called cathode.

When electrodes come in contact with electrolyte, a chemical reaction takes place inside the cell to produce electricity. Thus, it converts the chemical energy into electrical energy When electrodes are connected to the wires in a circuit, electricity passes through them.

Question 2.
What is a both? Write different types of bain How does an Incandescent bulb work? Does if save Are electrical energy?
Answer:

1. Bulb is an electric device which converts electrical energy into light energy.
2. There are different types at bulbs. They are 1) incandescent bulb, 2) Fluorescent bulb (Tube light), 3) CFL (Compact Fluorescent Lamp), 4) LED bulb, etc.
3. Incandescent bulb works on the principle of heating effect of electricity.
4. Incandescent bulb doesn’t save electrical energy. It consumes more electrical energy compared to CFL and LED lamps.

Question 3.
Write the differences between series and parallel connections of cells.
Answer:

Question 4.
Write the differences between series and parallel connections of bulbs.
Answer:

Question 5.
Explain the following :
a) Heating effects of electric current.
b) Magnetic effects of electric current.
Answer:
a) Heating effects of electric current:

1. The production of heart due to the flow of electricity through a wire is called heating effects of electricity.
2. Electric devices like electric stoves, room heaters, iron boxes, electric kettles, electric cookers, heaters, geysers, hair dryers work on the principle of heating effects of electric current.
3. All these appliances contain a heating element is called a filament.
4. Generally, a filament is made up of Nichrome in iron boxes and the filaments of an electric bulb is made of Tungsten.

b) Magnetic effects of electric current:

1. The production of magnetic force due to the flow of electricity through a wire is called magnetic effect of electricity.
2. The devices which act as magnets when electricity passes through them are called electromagnets.
3. The electric devices like loudspeakers, fan, bell, motor, mixer grinders, MRI machines, generators, metal detectors, mobile phones work on the principle of magnetic effect of electricity.
4. Magnetic effects produced in a coil which is wound around a soft iron due to the passing of electricity in the coil.

Question 6.
1) What is an electric shock?
2) Which situations lead to an electric shock?
3) What is the first aid for efectric shock?
4) How does CPR help to the person?
Answer:
1) An electric shock occurs when a person comes into contact with an electrical source. Electricity flows through a portion of the body causing a shock It leads to major damage, sometimes it may cause death.

2) i) Operating a switch with a wet hand.
ii) Removing plug pins when the switch is on.
iii) Using wires without insulation.
iv) Changing bulb when the switch is on.

3) i) When anybody gets an electric shock.
ii) First, cut off the power supply.
iii) If it is not possible, push away the person with a dry stick.
iv) If the shock is severe and the person is unconscious, give mouth-to-mouth artificial respiration.

4) Sometimes heart beat ceases, at that time keep your palms on his chest and press down and release until the heartbeat is recovered. This is called Cardio Pulmonary Resuscitation (CPR). Immediately take him to the hospital.

Question 7.
Fill in the table with suitable answers.

Answer:

Question 8.
Observe the given figures and answer the following questions.
Answer:

1) In which circuit bulbs are connected in parallel?
2) In which circuit electricity passes through only one path?
3) Which circuit represents household connections?
4) What happens if one bulb is damaged in circuit A?
5) In which circuit glow of bulb is enhanced?
Answer:

1. Circuit B
2. Circuit A
3. Circuit B
4. Circuit will be opened
5. Circuit A

Question 9.
Fill in the table.

Answer:

Question 10.
Draw the diagram of a dry cell and label the parts.
Answer:

Question 11.
Draw the symbols of given electrical components.
1) Cell 2) Battery 3) Bulb 4) Glowing bulb 5) Switch in ‘ON’ mode 6) Switch in ‘OFF’ mode 7) Fuse 8) Connecting wires.
Answer:

Question 12.
Here a circuit with real components are given. Draw the circuit by using symbols of the components.
Answer:

Answer:

Question 13.
Kalyan uses 5 LED bulbs of 9W for 10 hours, 3 fans of 60 W for 8 hours, 1 TV of 100 W for 6 hours in his house per day. Calculate the cost of his consumed electricity for a month at the rate of ₹ 10 per unit.
Answer:

Problems Given In The Lesson

Exercise – 1

The meter reading in Chandu’s house for the month of December 2020 is 29171 units. The meter reading in the previous month is 29062 units. Calculate how much he has to pay towards electricity bill in December. The unit cost is Rs.3.16.
Answer:

Exercise – 2

Suppose in a house there are 5 bulbs of 100W each, five of 60 W each, five of 40W each. All of them are used for five hours everyday. How many units of electricity is used in the month of February 2021? How much will they have to pay at Rs.2.80/- per unit?
Answer:

AP Board 7th Class Science 6th Lesson 1 Mark Bits Questions and Answers Electricity

I. Multiple Choice Questions

1. The positive electrode in a cell is called
A) Electrolyte
B) Anode
C) Cathode
D) Filament
Answer:
B) Anode

2. Which of the following converts chemical energy into electrical energy?
A) Cell
B) Bulb
C) Fan
D) Switch
Answer:
A) Cell

3. The container of a dry cell works as
A) Anode
B) Cathode
C) Electrolyte
D) None
Answer:
B) Cathode

4. A carbon rod with a metal cap in a cell works as
A) Anode
B) Cathode
C) Electrolyte
D) None
Answer:
A) Anode

5. Generally the chemical used in a dry cell is
A) Copper sulphate
B) Sodium chloride
C) Ammonium chloride
D) Potassium hydride
Answer:
C) Ammonium chloride

6. The lemon juice in a cell is acts as a
A) Anode
B) Cathode
C) Electrolyte
D) None
Answer:
C) Electrolyte

7. Dry cell is not used in
A) Torch light
B) Wall clock
C) Radio
D) Mobiles
Answer:
D) Mobiles

8. Assertion (A) : Dry cell is easy to move any where.
Reason (R) : Dry cell consists of also electrolyte in dried form.
A) A and R are correct and R is a correct reason to A
B) A and R are correct but R is not a correct reason to A
C) A is correct but R is incorrect
D) A is incorrect but R is correct
Answer:
A) A and R are correct and R is a correct reason to A

9. Generally, button cells are used in
A) Torch lights
B) Mobile phones
C) Wrist watches
D) Vehicles
Answer:
C) Wrist watches

10. 1) When switch is in ‘off position the circuit is a closed.
2) When switch is in’off position the bulb does not glow.
A) 1 is correct
B) 2 is correct
C) 1 and 2 are correct
D) 1 and 2 are wrong
Answer:
B) 2 is correct

11. Which of the following consumes more power than others?
A) Incandescent bulb
B) Fluorescent bulb
C) CFL
D) LED
Answer:
A) Incandescent bulb

12. Fuse wire is made of
A) Low melting point wire
B) High melting point wire
C) No melting point wire
D) A or B
Answer:
A) Low melting point wire

13. Which of the follow device prodect the electrical home appliances?
A) Fuse
B) MCB
C) A and B
D) Filament
Answer:
C) A and B

14. A siaifsie decftfc circuit amwBlmg of
A) a battery
B) a bulb
C) a switch
D) above all
Answer:
D) above all

15. This is the symbol of
A) a cell
B) a battery
C) two switches
D) fuse
Answer:
B) a battery

16. This symbol represents
A) a cell
B) an open switch
C) a closed switch
D) an open cell
Answer:
B) an open switch

17. WMADftefofloif mg represents a glowing bulb?

Answer:
A

18. On series connection has
A) Only two paths
B) Only one path
C) More than one path
D) None
Answer:
B) Only one path

19. If a number of cells are connected in series the brightness of the bulb is
A) Enhanced
B) Reduced
C) As usual
D) A or B
Answer:
A) Enhanced

20. If a number of cells are connected in parallel the brightness of the bulb is
A) Enhanced
B) Reduced
C) As usual
D) A or B
Answer:
C) As usual

21. In which connection one of the cells are removed the circuit does not open?
A) Series
B) Parallel
C) A and B
D) None
Answer:
B) Parallel

22. If a number of bulbs are connected in series the brightness of the bulb is
A) Enhanced
B) Reduced
C) Sanafe issmre
D) Aor B
Answer:
B) Reduced

23. If a number of bulbs are connected in parallel the brightness of the bulb is
A) Enhanced
B) Reduced
C) Remains same
D)A or B
Answer:
C) Remains same

24. Household devices are connected in
A) Series
B) Parallel
C) A or B
D) None
Answer:
B) Parallel

25. Which of the following gives light by glowing in Bulbs?
A) Nichrome
B) Tungsten
C) Alnico
D) Copper
Answer:
B) Tungsten

26. Generally filament in iron boxes are made up of
A) Nichrome
B) Tungsten
C) Alnico
D) Copper
Answer:
A) Nichrome

27. The devices which acts as magnets when electricity passes through them
A) Electric kettles
B) Electric heaters
C) Electromagnets
D) MCB
Answer:
C) Electromagnets

28. Which of the following works on principle of magnetic effect of electricity?
A) Electric rice cooker
B) Thermometer
C) Electric bell
D) Electric bulb
Answer:
C) Electric bell

29. Which of the following is required to make an electromagnet?
A) Coiled copper wire
B) Nail
C) Electricity
D) Above all
Answer:
D) Above all

30. Which of the following property can levitate a magnetic object?
A) Heat effect of electricity
B) light effect of electricity
C) Chemical effect of electricity
D) Magnetic effect erf etedtricity
Answer:
D) Magnetic effect erf etedtricity

31. Electromagnets are
A) permanent magnets
B) temporary msassets
C) not the magnets
D) bad conductors
Answer:
A) permanent magnets

32. 1 kilo watt =
A) 1000 watts
B) 100 watts
C) 1/1000 watts
D) 1/100 watts
Answer:
A) 1000 watts

33. 1 unit of electricity means
A) 1 WH
B) 1 KWH
C) 1000 KWH
D) 1/1000 KWH
Answer:
B) 1 KWH

34. Immediate action to be tacken when an electric shock occurs is
A) pouring erf water
B) danger with the device
C) Cut off power supply
D) Expiry date of the device
Answer:
C) Cut off power supply

35. Indicates
A) Power saving erf the device
B) Danger with the device
C) Quality erf the device
D) Expiry date of the device
Answer:
C) Quality erf the device

II. Fill in the blanks

1. …………………. is a device used to generate electricity
2. The chemical componesrf that conducts electricity is called …………………. .
3. The negative electrode is called …………………. .
4. The …………………. electrode is called anode.
5. A cell converts the …………………. energy into …………………. energy.
6. The positive and negative terminals are called …………………. .
7. A group of …………………. is called a battery.
8. When switch is in ‘ON’ mode, the circuit is …………………. .
9. An ordinary bulb gives …………………. and …………………. .
10. CFL means …………………. .
11. LED means …………………. .
12. The electrical appliance with more stars consumes …………………. electricity.
13. …………………. protects home appliances from the excess of electricity flows through them.
14. Generally, fuse wire made of …………………. melting point.
15. MCB means …………………. .
16. …………………. is better, when compared to electric fuse.
17. A …………………. is a graphical representation of an electrical circuit.
18. The electrical symbol of fuse is …………………. .
19. In …………………. connection of cells life of battery increases.
20. Nichrome wire gets …………………. when electricity passed through it.
21. The production of …………………. due to the flow of electricity through a wire is called heating effect of electricity.
22. Household electricity is measured in …………………. .
23. 1 …………………. = 1000 watts.
24. KWH means …………………. .
25. A …………………. occurs when a person comes into contact with an electrical source.
26. Electricity flows through a portion of the body causing a
27. CPR means …………………. .
28. ISI means …………………. .
29. ISI mark ensures …………………. of the appliances.
Answer:

1. A cell
2. Electrolyte
3. Cathode
4. positive
5. chemical, electrical
6. electrodes
7. cells
8. closed
9. heat, light
10. Compact Fluorescent Lamp
11. Light Emitting Diode
12. less
13. Fuse
14. Low
15. Miniature Circuit Breaker
16. MCB
17. circuit diagram
18. 
19. parallel
20. heated up
21. heat
22. KWH or units
23. kilo watt
24. kilo watt hour
25. Electric
26. shock
27. Cardio Pulmonary Resuscitation
28. Indian Standards Institutions
29. quality

III. Match the following

1.

Answer:

2.

Answer:

3.

Answer:

4.

Answer:
A – 7, B – 3, C – 1, D – 5, E – 6, F – 2, G – 4.

Do You Know?

→ In 1752, Franklin conducted the kite experiment to show that lightning was also electricity. He flew a kite during a thunderstorm. He tied a metal key to the string of the kite to conduct the electricity.

→ LED (Light Emitting Device) has two legs. Long leg indicates positive(+ve) and short leg indicates negative (-ve). Early LEDs produced only red light, but modern LEDs can produce several different colors, including red, green and blue light. LEDs are used as indicators in mobiles, laptops, T.V remotes etc.

→ A switch can be placed anywhere in the circuit and a cell can be connected in any direction in the electric circuit.

→ The scientist Oersted discovered that a magnetic field is produced around a current carrying conductor. Electromagnets are made by using the relationship between electricity and magnetism.

→ Michael Faraday made a magnet to revolve around a coil of wire which produced electricity. He invented electric generator or dynamo and transformer.