AP State Board Notes

Students can go through AP State Board 10th Class Social Studies Notes Chapter 2 Ideas of Development to understand and remember the concept easily.

AP State Board Syllabus 10th Class Social Studies Notes Chapter 2 Ideas of Development

→ Development involves thinking about and adevùig goals of a better life for all and more quality among all

→ All persons do not have the same notion of development.

→ Persons seek things that can fulfill their aspirations or desires.

→ At times, two persons or groups of persons may seek things that are conflicting.

→ Besides seeking more income, people also seek equal treatment, freedom, security, respect from others, and resent discrimination.

→ More income means more of all things that human beings need. c& Average income, which is the total income of the country divided by the total population is also called per capita income.

→ World Development Report brought out by the World Bank in 2013 classified the countries into 3 groups.

→ Countries with per capita income of US $ 12,600 and above per annum in 2012 are called high-income countries or rich countries,

→ Countries with a per capita income of above US $1,035 and below the US $ 12,600 per annum in 2012 are called middle-income countries.

→ Countries with a per capita income of US $1,035 or less per annum in 2012 are called low-income countries.

→ The rich countries, excluding countries of west Asia and certain other small countries, are called developed countries.

→ The goods and services or required facilities that are provided by the government or society are called public facilities.

→ Human Development Report compares the countries, the educational levels of people, their health status, and per capita income as measures of development.

→ Human Development Report 2013 is the Human Development Index ranking among the 177 countries in all.

→ Per capita income is calculated in US Dollars for all countries so that one can compare all the countries.

→ A small country in our neighborhood, Sri Lanka, is much ahead of India in every indicator of development.

→ The schooling revolution in Himachal Pradesh provided infrastructure in education, and, both the government and society complemented each other to achieve great indicators of education.

→ In the year 2005, the average spending on education by the government in Indian states was Rs. 1,049 per child, Himachal Pradesh was spending Rs. 2,005 per child.

→ Development entails a mix of goals.

→ India, a decade ago was a less developed country, and now transformed into a developing country or middle-income country.

→ Every Indian would like to see India as a developed country.

→ Per capita income: Total income of the country divided by the fatal population.

→ Human development: Comparing the countries and reporting their development based on the educational levels of people, their health status, and per capita income

→ Public facilities: The facilities, i.e., goods and services that are provided by the government or society

→ Education and health Indicators: The indicators which show the educational æd health conditions of the people like average years of schooling, life expectancy at birth, etc.

→ Development: Achieving the goals of making life better for all and bringing more equality

→ The idea of development: Sk the thing that is most important for one which fulfills his developmental goal or aspiration

→ Material things: The things that one can buy with money

→ Non-material things: The things that one cannot buy with money like equal treatment, freedom, etc.

→ High-income countries: Countries with annual per capita income of US $ 12,600 and above in 2012.

→ Middle-income Countries with per capita income of above US $ 1,035 countries and below LIS $12,600 per annum in 2012.

→ Low-income countries: Countries with per capita income of below US $ 1, 35 per annum in 2011

→ Infant Mortality Rate: Out of 1,000 live children burn, the number of children who die within one year.

→ Literacy Rate: The percentage of the literate population in the 7 years and above age group.

→ Net Attendance Rate: Out of the total number of children in the age group 6- 17 years the percentage of children attending school.

→ HDI: Human Development Index

→ Life expectancy at birth: Average expected length of life of a person at the time of birth.

→ Average years of schooling: Average number of years of education received by people that age 25 years and above.

→ Expected years of schooling: Number of years of schooling that a child at school entrance age can expect to receive given the present enrollment rates.

Students can go through AP State Board 10th Class Social Studies Notes Chapter 1 India: Relief Features to understand and remember the concept easily.

AP State Board Syllabus 10th Class Social Studies Notes Chapter 1 India: Relief Features

→ World landforms originated from two giant lands namely Angara land (Laurasia) and Gondwana land.

→ The Indian Peninsula was part of Gondwana land.

→ The Himalayan ranges run in the west-east direction in the form of an arch with a distance of about 2400 km.

→ The northernmost range is known as Himadri or Greater Himalayas.

→ The portion of the range found south of the Greater Himalayas is called ’Lesser Himalayas’.

→ The southernmost range of the Himalayas is the Shivaliks.

→ The valleys lying between the Lesser Himalayas and Shivalik ranges are called Duns.

→ The Himalayas are the reason for summer rains and monsoon type of climate in regions that are beyond the Western Ghats of India.

→ The interaction of three Himalayan rivers Indus, Ganga, and the Brahmaputra, and their tributaries resulted in the formation of the great northern plain.

→ In the western part of the great northern plain, the ’Doab’ features dominate the fertile land between the two rivers.

→ The Indian plateau is also known as the peninsular plateau as it is surrounded by the sea on three sides.

→ The peninsular plateau consists of two broad divisions, namely, the central I highlands (Malwa plateau) and the Deccan Plateau.

→ The Western Ghats lie parallel to the west coast and they extend for 1600 km.

→ The Eastern Ghats extend from Mahanadi valley in the north to Nilgiris in the south, The highest peak in the Eastern Ghats is Aroma Konda found at Chintapalli (1680 m) in Andhra Pradesh.

→ The Thar desert is located on the leeward side of Aravalis and receives very little rainfall, ranging from 100 to 150 mm per year.

→ ’Luni’ is the only river in the Thar desert area.

→ The southern part of the peninsular plateau is bordered by narrow coastal strips along the Arabian Sea on the west and the Bay of Bengal on the east.

→ Coastal zone enables rich fishing resources.

→ There are two groups of Islands – Andaman and Nicobar Islands stretched in the Bay of Bengal and Lakshadweep Islands in the Arabian Sea.

→ There is a vast diversity in the landforms in which Indian people live.

→ Some areas are irrigated by the mighty rivers flowing from the Himalayas and some by the rainfed rivers from the Western Ghats and its forests.

→ Many places are located in the valleys and others in the mountains.

→ Perennial: LastIng a very long time, or happening repeatedly or all the time

→ Coral reefs: A bank of coral, the top of which can sometimes be seen just above the sea

→ Coastal plains: The East Coastal plain is between the Eastern Ghats and the Bay of Bengal, the West Coastal plain Is between the Western Ghats and the Arabian sea.

→ Peninsula: A stretch of land surrounded by water on three sides

→ Angara land: Laurasia = The northerly of the two continents into which the earth’s landmass was once divided

→ Gondwana land: The southerly of the two continents Into which the earth’s landmass was once divided

→ Shivalik: The southernmost range of the Himalayas

→ Purvanchal: The divisions of the Himalayas In Arunachal Pradesh beyond the Dihang valley

→ Laurasia: Angara land

→ Duns: The valleys lying between the lesser Himalayas and Shivalik ranges

→ Leeward: The side or direction that Is sheltered from the wind. e.g. by a range of mountains

→ Relief features: The features which exhibit differences in the elevation of any part of the earth’s surface

→ Relief maps: Maps that seek to depict the surface relief of an area in three dimensions though not necessarily to scale

→ WeatherIng: The decay and disintegration of rocks of the earth’s crust by exposure to the atmosphere

→ DeposItion: The laying down of solid material that has been carried from a distant part of earth’s crust by natural agents like a river, wind, etc.

→ Erosion: The process of wearing away of the land surface by various natural agents like water, ice, wind, etc.

→ Landform: The shape, form, and nature of a feature of the earth’s land surface

→ Folding process: The formation of a bend In rock strata due to movements of the earth’s crust

→ Fold mountains: Mountains that have been thrown up into a massive fold or ridge by earth movements

→ Basin: A shallow structural down old In earth’s crust

→ River basin: The area drained by a single river system

→ Doab: The fertile land between two rivers

→ Topography: A detailed description or representation of both the natural and artificial features of an area Himadri Greater Himalayas = The northernmost range of the Himalayas.

→ Lesser Himalayas: Himachal The portion of the range found south of the Greater Himalayas.

Students can go through AP State Board 10th Class Physical Science Notes Chapter 12 Carbon and its Compounds to understand and remember the concept easily.

AP State Board Syllabus 10th Class Physical Science Notes Chapter 12 Carbon and its Compounds

→ Carbon always forms covalent bonds.

→ Carbon is present in all substances of animal and vegetable origin.

→ The ability of carbon to unite with an indefinite number of carbon atoms in straight branched or cyclic chains is known as catenation.

→ Carbon and hydrogen combine together in different proportions to form a large number of compounds called hydrocarbons.

→ There are two types of hydrocarbons – saturated and unsaturated.

→ Alkanes are represented by the general formula C_nH_2n+2.

→ Alkenes are represented by the general formula C_nH_2n.

→ Alkynes are represented by the general formula C_nH_2n-2.

→ Organic compounds having the same functional group and common properties but differing in the molecular formula from the next member by one CH₂ group, form a homologous series and such compounds are called homologs.

→ Compounds with the same molecular formula but different structural formulas are known as isomers.

→ The decomposition of alkanes on heating in the absence of oxygen is known as cracking.

→ Methane is prepared by heating a mixture of sodium acetate and soda-lime.

→ When ethanol is heated with an excess of concentrated H₂SO₄ at 160° C ethane gas is produced.

→ Natural gas is a mixture of gaseous hydrocarbons mainly methane, ethane, propane, and butane.

→ Natural gas is used as a fuel.

→ Compressed Natural Gas (CNG) is used as an alternative to petrol as automobile fuel.

→ Ethanol and Ethanoic acid are important carbon compounds in our daily life.

→ The molecules of soap are sodium or potassium salts of long-chain carboxylic acids.

→ Detergents are ammonium or sulfate salts of long-chain carboxylic acids.

→ The action of soaps and detergents is based on the presence of both hydrophobic and hydrophilic groups in the molecule and this helps to emulsify the oily dirt and hence its removal.

→ Alcohols are organic compounds that contain hydroxyl group (-OH) bonded to a carbon atom.

→ Alcohols are neutral to litmus.

→ Alcohols are poor conductors of electricity.

→ Alcohols react with sodium to liberate hydrogen gas.

→ Carbon chains may be in the form of straight chains, branched chains of rings.

→ Saturated hydrocarbons on combustion give carbon dioxide and water with the liberation of heat.

→ Unsaturated hydrocarbons undergo addition reactions while saturated hydrocarbons undergo substitution reactions.

→ The occurrence of the same element in two or more different forms is known as allotropy.

→ Hybridization: The redistribution of orbitals of almost equal energy in individual atoms to give an equal number of new orbitals of equivalent energy is called hybridization.

→ Allotropy: The property of an element to exist in two or more physical forms having more or less similar chemical properties but different physical properties is called allotropy.

→ Diamond: A transparent form of carbon that is the hardest known material

→ Graphite: A soft dark grey or black form of carbon that occurs naturally as a mineral.

→ Buck minster fullerene: A hollow molecule, spherical like a football, has 20 hexagons and 12 pentagons, having 60 vertices on its surface and made from 60 atoms of carbon.

→ Nanotubes: Nanotubes are another allotropic form of carbon.

→ Catenation: Any element forms bands among its own atoms to give big molecules. This property is called catenation.

→ Tetravalency: The valency of a carbon atom is four. This valency of carbon otherwise is called tetravalency.

→ Hydrocarbons: The compounds containing only carbon and hydrogen in their molecules are called hydrocarbons.

→ Alkanes: Hydrocarbons containing only single bonds between carbon atoms are called alkanes.

→ Alkenes: Hydrocarbons containing at least one double bond between carbon atoms are called alkenes.

→ Alkynes: Hydrocarbons containing at least one triple bond between carbon atoms are called alkynes.

→ Saturated hydrocarbons: The hydrocarbons containing C – C single bonds are known as saturated hydrocarbons.

→ Unsaturated hydrocarbons: The hydrocarbons containing at least one double bond (C = C) or containing at least one triple bond (C C) between the two carbon atoms are called unsaturated hydrocarbons.

→ Functional group: An atom or a group of atoms in an organic molecule, which is responsible for the compound’s characteristic reactions and determines its properties is known as a functional group.

→ Isomerism: The phenomenon of possessing the same molecular formula but different properties by the compounds is known as isomerism.

→ Homologous series: The series of carbon compounds in which two successive compounds differ by – CH₂ unit is called homologous series.

→ Nomenclature: The naming of organic compounds is known as nomenclature.

→ Combustion: The process of burning carbon or carbon compound in excess of oxygen to give heat and light is called combustion.

→ Oxidation: The addition of oxygen to a given compound or removal of hydrogen from the compound is called oxidation.

→ Addition reaction: The reaction in which an unsaturated hydrocarbon combines with another substance to give a single product is called an addition reaction.

→ Substitution reaction: The reaction in which one or more hydrogen atoms of a hydrocarbon are replaced by some

other atoms (like chlorine) is called a substitution reaction.

→ Ethanol: Ethanol is the second member of the homologous alcoholic series. Its formula is C₂H₅OH.

→ Ethanoic adds: It is the second member of the homologous series of carboxylic acids. Its formula is CH₃COOH.

→ Ester: Esters are organic compounds that contain the functional group – COO^– and whose general structural formula is

where R = H or an alkyl group and R’ is an alkyl group. R and R’ may be the same or different.

→ Esterification: The reaction in which a carboxylic acid combines with an alcohol to form an ester is called esterification.

→ SaponIfication: The process of making soap by the hydrolysis of fats and oils with alkalies is called saponification.

→ Micelle: A spherical aggregate of soap molecules in the soap solution in water is called a micelle.

→ Enrico Fermi (1901 – 1954)

• Enrico Fermi was born in Rome on September 29, 1901.
• He became a professor of theoretical physics at the University of Rome in 1927.
• Fermi received the Nobel Prize in 1938 for his “discovery of new radioactive elements produced by a neutron in radiation, and for the discovery of nuclear reactions brought about by slow neutrons”.
• Fermi’s momentous accomplishment caused him to be recognized as one of the great scientists of the 20th century.

Students can go through AP State Board 10th Class Physical Science Notes Chapter 11 Principles of Metallurgy to understand and remember the concept easily.

AP State Board Syllabus 10th Class Physical Science Notes Chapter 11 Principles of Metallurgy

→ Metallurgy is the process of extraction of metals from their ores and the preparation of alloys.

→ Metals like gold (Au), silver (Ag) and copper (Cu) are available in nature in a free state as they are least reactive.

→ The elements or compounds of the metals which occur in nature in the earth’s crust are called minerals.

→ The minerals from which the metals are extracted without economical loss are called ores.

→ The removal of unwanted rocky material from ore before it converts into metal is called concentration.

→ Air under pressure is blown to produce froth in water is called froth flotation.

→ If the ore or impurity, one of them is magnetic and the other is non-magnetic, they are separated using electromagnets.

→ Arranging the metals in decreasing order of their reactivity is known as activity series.

→ Extraction of the metals at the top of the activity series is the electrolysis of their fused compounds.

→ Sulphide ores are converted into oxides by heating them strongly in excess of air. This process is known as “roasting”.

→ When sulphide ore of copper is partially roasted, the rest of the sulphide ore reacts with oxide and forms the metal. This is called auto reduction.

→ In displacement reactions, a more active metal displaces a less active metal from its compound.

→ Displacement reactions are highly exothermic.

→ The reaction of iron (III) oxide (Fe₂O₃), with aluminium, is used to join railings of railway tracks or cracked machine parts. This reaction is known as the thermite reaction.

→ Metals at bottom of the activity series are often found in a free state.

→ The process of obtaining the pure metal from the impure metal is called refining of the metal.

→ The impurities are removed either as gases or get oxidized and form scum (slag) over the surface of the molten metal. This is called poling.

→ Blister copper is purified by poling.

→ Distillation is very useful for the purification of low boiling metals like zinc and mercury-containing high boiling metals as impurities.

→ Metals are not available as free elements on earth.

→ Human history in terms of materials had the Bronze age and Iron age. Pertaining to metals, they started to use bronze and iron.

→ Bauxite ore contains 50-70% aluminium oxide.

→ Ores of many metals are oxides.

→ The impurities of ore are called gangue.

→ The concentration of ore can be done in 4 methods.

1. Handpicking
2. Washing
3. Froth flotation
4. Magnetic separation.

→ The only viable method to extract metals like K, Na, Ca, Mg and Al is electrolysis.

→ Minerals: The elements or compounds of the metals which occur in nature in the earth’s crust are called minerals.

→ Ores: The minerals from which the metals are extracted without economical loss are called ores.

→ Froth flotation: This method is mainly useful for sulphide ores which have no wetting property whereas the impurities get wetted.

→ Thermite process: The reaction between metal oxides and aluminium.

→ Distillation: Separation of low boiling metals like zinc and mercury from high boiling metals as impurities.

→ Poling: The molten metal is stirred with logs of greenwood.

→ Liquation: A low melting metal like a tin can be made to flow on a soapy surface to separate it from high melting impurities.

→ Electrolytic refining: The electrolysis process is used to purify the metal.

→ Smelting: Smelting is a pyrochemical process in which the ore is mixed with flux and fuel and then strongly heated.

→ Roasting: Sulphide ores are converted into oxides by heating them strongly in excess of air. This process is known as roasting.

→ Calcination: Calcination is a pyrochemical process in which the ore is heated in the absence of air.

→ Blast furnace: Furnace used for smelting.

→ Reverberatory furnace: Furnace used for roasting.

→ Metallurgy: It is the process of extraction of metals from their ores and the preparation of alloys.

→ Gangue: The impurities obtained from ore like days are called gangue.

→ Activity series: Arranging the metals in decreasing order of their reactivity is known as activity series.

→ Thermite reaction: The reaction of iron (III) oxide (Fe₂O₃), with aluminium, is used to join railings of railway tracks or cracked machine parts. This reaction is known as a thermite reaction.

→ Refining of the metal: The process of obtaining the pure metal from the impure metal is called refining of the metal.

→ Corrosion: Metallic objects are slowly coated with oxides or other salts of the metal and form a thin layer which is called corrosion.

→ Rusting: Corrosion of iron is called rusting.

→ Flux: Flux is a substance added to the ore to remove the gangue from it by reacting with ore.

→ Furnace: Furnace ¡s the one which is used to carry out pyrochemical processes in metallurgy.

→ Hearth: The hearth is the place inside the furnace where the ore is kept for heating.

→ Chimney: Chimney is the outlet through which flue (waste) gases go out of the furnace.

→ Concentration or Dressing: concentration is the removal of the unwanted rocky material as possible before the ore is being converted into metal.

→ Auto (self) reduction: When sulphide ore of copper is partially roasted it gives oxide when the supply of air is stopped, the rest of sulphide reacts with oxide and forms the metal and SO₂ is called auto reduction.

→ Displacement reactions: The reaction in which a more active metal displaces less active metal from its compound is called displacement reaction.

→ Firebox: Firebox is the part of the furnace where the fuel is kept for burning.

→ Sir Henry (1813 – 1898):

• Bessemer Sir Henry was born in Chariton on January 19, 1813.
• He invented a new process for the metallurgy of steel, which became quite famous.
• He Invented a device named after him as “Bessemer Converter” and the phenomenon is called Basscmerisation”.

Students can go through AP State Board 10th Class Physical Science Notes Chapter 10 Electromagnetism to understand and remember the concept easily.

AP State Board Syllabus 10th Class Physical Science Notes Chapter 10 Electromagnetism

→ Magnetic flux density (B) is defined as the ratio of flux passing through a plane perpendicular to the field and the area of the plane.

→ To find the direction of the magnetic field due to the straight conductor-carrying conductor, we use the right-hand thumb rule.

→ The current-carrying wire produces a magnetic field.

→ The magnetic induction field of the earth is approximately BH = 0.38 × 10^-4 Tesla.
Here 1 Tesla = 10⁴ Gauss.

→ F = qvB sin θ and F = ILB sin θ.

→ The magnitude of magnetic field induction at the center of the coil is always
B ∝ \(\frac{\mathrm{Ni}}{\mathrm{r}}\)
Here N = Number of turns ; i = Current; r = Radius of the coil.

→ In an electric motor, electrical energy is converted into mechanical energy.

→ Electromagnets are used to lift heavy iron pieces. They are fitted on cranes lifting heavy objects of scrap iron.

→ Faraday’s law: The induced EMF generated in a closed loop is equal to the rate of change of magnetic flux passing through it.

→ Electromagnets are used in electric bells, electric horns, telephone receivers, electric relays, microphones, radio sets, television, and loudspeakers, etc.

→ Lenz’s law: The induced current set up in the coil is in such a direction that it opposes the changes in the flux.

→ Permanent magnets are used in galvanometers, voltmeters, ammeters, speedometers, etc.

→ When a conductor of length ‘V moves perpendicular to field B with a speed v then the potential difference (voltage) developed between the ends of the conductor is B/v. This EMF is called motional EMF.

→ The polarity of electromagnets can be reversed by changing the direction of the electric current.

→ In generators, mechanical energy is converted into electrical energy.

→ The polarity of a permanent magnet cannot be reversed.

→ The effect of magnetic field on moving charges has been used to build machines, called particle accelerators. Ex: Cyclotron.

→ The electric force is collinear, whereas magnetic force is perpendicular to the magnetic field.

→ The ratio of magnetic force to electric force is very negligible.

→ In domestic circuits, the series arrangement is not used.

→ To protect electric appliances like television sets, computers, which are highly expensive, cartridge fuses are used.

→ The cost of generation of A.C is less than the cost of generation of D.C.

→ A.C can be transmitted to distant places without much loss of electric power than D.C.

→ A.C can be easily connected to D.C.

→ A.C is more dangerous than D.C.

→ In the process of electrolysis, D.C. is used.

→ If the number of turns, area, speed of the rotation of armature increases induced emf is increased.

→ An electric fuse is made of a material of low melting point.

→ Magnetic flux: The number of lines passing through the plane of area perpendicular to the field is called magnetic flux. It is denoted by ‘Φ’. Its SI unit is Weber.

→ Magnetic flux density: Magnetic flux per unit area is known as magnetic flux density. This is also known as magnetic induction.
∴ B = \(\frac{\phi}{A}\)
Unit → Weber/metre2 or Tesla

→ Electric motor: It ¡sa device which converts electrical energy into mechanical energy.

→ Slip rings: The reverse of current in an AC dynamo occurs because the two ends of the armature coil are in permanent contact with the same two slip rings and S2

→ Induced current. Whenever there ¡s a continuous change of magnetic flux linked with the closed coil, the current is generated in the coil. This is known as induced current.

→ Induced EMF: The pushing or pulling of the magnet causes a change in magnetic flux linked to the coils which cause induced EMF.

→ Electric generator: It is a device that converts mechanical energy into electrical energy.

→ DC and AC currents: An electric current whose magnitude is either constant or variable but the direction of flow in a conductor remains the same is called Direct Current. It is denoted by DC. An electric current whose magnitude changes with the time and direction reverses periodically is called Alternate Current. It is denoted by AC.

→ rms values : I_rms = \(\frac{\mathrm{I}_{0}}{\sqrt{2}}\) and V_rms = \(\frac{\mathrm{V}_{0}}{\sqrt{2}}\)
Here AC current and AC voltage are expressed in terms of RMS values. Here I and vo are the peak values of AC current and AC EMF.

→ Magnetic compass: It is a simple device to find directions. It is a small magnet that is pivoted at its center so that it can rotate in its horizontal plane, and always point towards the north-south direction of the earth, after coming to rest.

→ Ampere’s swimming rule: Imagine a swimmer along the length of the conductor in which current flows. Then the left-hand motion of the person gives the direction of deflection of the north pole of the magnetic needle placed near to it.

→ Electromagnet: An electromagnet is a temporary strong magnet and is just a solenoid with its winding on a soft iron core.

→ Permanent magnet: A permanent magnet is made from steel. As steel has more retentivity than iron, it does not lose its magnetism easily.

→ Flemmings left-hand rule: When a current-carrying wire is placed in a magnetic field, a force is exerted on the wire. According to Flemming’s rule, hold the forefinger, middle finger, and thumb of the left hand at right angles to one another, then the forefinger points in the direction of force due to the magnetic field. Middle finger points in the direction of current and the thumb points in the direction of motion of the conductor.

→ Flemming’s right-hand rule: Stretch the right hand such that forefinger, middle (Dynamo Rule) finger, and thumb are mutually perpendicular to each other. Forefinger points the direction of the field. The middle finger points the direction of the induced current. Thumb points the direction of motion of the conductor.

→ Energy meter or KWH meter: The cable connected to the energy meter records the electricity consumption of the house in kilowatt-hour.

→ Main Fuse: The live wire coming out from the output terminals or KWH meter has another fuse which is called the main fuse.

→ Electric Fuse: It is a device used in series to limit the current in an electric circuit so that it easily melts due to overheating when excessive current passes through it.

→ Armature: Armature is a coil that consists of a large number of turns of insulated copper wire wound over a soft iron core. it revolves around an axle between two poles of a strong magnet.

→ Short-circuiting: When live wire and neutral wire come in direct contact, the resistance of the wire becomes very small. Then huge current flows through the circuit and produces a large amount of heat in the circuit and the circuit catches fire. This is known as short-circuiting.

→ Michael Faraday:

1. Faraday was a British chemist and physicist who contributed significantly to the study of electromagnetism and Pedro chemistry.
2. He was born on 22 September 1791 in South London.
3. 1831 Faraday discovered electromagnetic Induction and the principle behind the electric transformer and generator.
4. As a chemist, Faraday discovered Benzene, Invented the early form of Bunsen Burner, and the system of oxidation numbers.
5. The unit of electric capacity is ‘Farad which is named after him.

→ (Hans Christian Oeited(1777 – 1851):
One of the leading scientists of the f 9th century; played a crucial role In understanding electromagnetism. He gave lectures which were quite popular among the public and also learned a lot during the tours. During one such lecture In April 1820, Oersted carried out an experiment that was never performed before. He placed a Compass needle underneath a wire and then turned on the electric current. The needle of the magnetized compass showed movement.

Oersted recognized the significance of what he had ‚ust done. Earlier, It was believed that electricity and magnetism were two dill event forces. Oersted had demonstrated that they were. Interconnected. Through this observation, he showed that electricity and magnetism Were ie1ated phenomena. Some scientists, Influenced by this experiment, continued With the modern field of “electromagnetism”. Their research resulted In several new scientific theories and various vital Inventions like the dynamo and the electric motor, Crested technologies such as the radio, television, and fiber optics. The unit of magnetic field strength Is named the Oersted In his honor. Oersted was made a foreign Academy of science in 1822.

Students can go through AP State Board 10th Class Physical Science Notes Chapter 9 Electric Current to understand and remember the concept easily.

AP State Board Syllabus 10th Class Physical Science Notes Chapter 9 Electric Current

→ A negative charge flows through an electric wire when it is connected to an electric circuit.

→ Lightning is an electric discharge between two clouds or between clouds and the earth. This is an example of the motion of charge in the atmosphere.

→ In a circuit, the battery stores chemical energy, and this energy converts into electric energy.

→ The material which transfers energy from the battery (source) to the bulb (consumer) is called a conductor.

→ Electric charge (I) = \(\frac{\text { Electric charge (Q) }}{\text { Time interval (t) }}\)

→ The SI unit of the electric current is ampere (A).

→ 1 Ampere = \(\frac{1 \text { coulomb }}{1 \text { second }}\)

→ The electrons in the conductor move with a constant average speed called drift speed or drift velocity.

→ The charge carriers in a conductor are electrons. The magnitude of the electric charge is 1.602 × 10^-19 C.

→ The electron density of copper is 8.5 × 10²⁸ m^-3.

→ The direction of the electric current is the direct flow of positive charges.

→ An ammeter is used to measure electric current. It is always connected in series to the circuit. Work done by the electric force on the unit positive charge to move it through a distance is called the potential difference. It is denoted by V.

→ V = \(\frac{W}{q}=\frac{\text { Workdone }}{\text { Charge }}=\frac{\text { Joule }}{\text { Coulomb }}\)

→ Potential difference is also called voltage. The SI unit of potential difference is volt (V).

→ The amount of charge accumulated on the plates depends on the nature of the chemical used in the battery.

→ The direction of the electric field is from positive terminal to negative terminal in the conductor.

→ Electromotive force (emf) is defined as the work done by the chemical force to move unit positive charge from negative terminal to positive terminal of the battery.

→ A voltmeter is used to measure potential difference or emf across an electric device like a battery.

→ \(\frac{\mathrm{V}}{\mathrm{I}}\) is constant. This constant is called the resistance of the conductor.

→ According to Ohm’s law, the potential difference between the ends of a conductor is directly proportional to the electric current passing through it at a constant temperature.

→ The SI unit of resistance is Ohm (Ω).

→ 1 Ohm = \(\frac{1 \text { Volt }}{1 \text { Ampere }}\)

→ Based on Ohm’s law materials are classified into two categories. They are ohmic conductors and non-ohmic conductors.

→ Metals obey Ohm’s law. They are called ohmic conductors.

→ LEDs are non-ohmic conductors. They don’t obey Ohm’s law.

→ Ohm’s law is not applicable to gaseous conductors and semi-conductors.

→ The resistance of a conductor is defined as the obstruction to the motion of the electrons in a conductor.

→ The material which offers resistance to the motion of electrons is called a resistor.

→ The resistance of the human body generally varies from 100 Ω (if the body is wet with salt water) to 5,00,000 Ω (if the skin is very dry).

→ The electric shock is a combined effect of potential difference, electric current, and resistance of the human body.

→ Temperature, nature of the material, length of the conductor, and cross-section area are the factors that affect resistance.

→ R = \(\frac{\rho l}{A}\) (p = density, l = length of the conductor, A = the cross-section area)

→ The filament of an electric bulb is made of tungsten.

→ The melting point of tungsten is 3422° C.

→ Semiconductors are used to make diodes, transistors, and integrated circuits.

→ A closed path created by the connecting wires through a battery along which the electrons conductor is called a circuit.

→ If the current drawn by a resistor is equal to the current drawn by the combination of resistors, then the resistor is called an equivalent resistor.

→ Two or more resistors are said to be connected in series if the same current flows through them.

→ Two or more resistors are said to be connected in parallel if the same potential difference exists across them.

→ According to Kirchhoff,
“At any junction point in a circuit where the current can divide, the sum of the currents into the junction must equal the sum of the currents leaving the junction.” This law is called the junction law.

→ According to Kirchhoff,
“The algebraic sum of the increases and decreases in potential difference across various components of a closed circuit loop must be zero.”

→ Electric power = V × I = voltage × current (I).

→ SI unit of power is the watt.

→ Electrical energy is the product of power and time.
E = power × time

→ Units of electrical energy are W and KWH (unit).

→ Charge: Positive or negative particles present in an electric circuit.

→ Potential difference: Work done by the electric force on the unit positive charge to move it through a distance.

→ Electric current: The ordered motion of electrons. (OR) The amount of charge crossing any cross-section of the conductor in one second.

→ Multi-meter: It is an electronic measuring instrument that combines several measurement functions in one unit.

→ Ohm’s law: V = IR; The potential difference between the ends of a conductor is directly proportional to the electric current passing through it at a constant temperature.

→ Resistance: The obstruction to the motion of the electrons in a conductor.

→ Resistivity (ρ): Resistance offered by a conductor having unit length and unit cross-section area. (constant in R = \(\frac{\rho l}{A}\))

→ Kirchhoff’s laws: Two simple rules of Kirchhoff applicable to any DC circuit containing batteries and resistors connected in any way.

→ Electric power: The product of voltage and current.

→ Electric energy: The product of electric power and time.

→ Conductivity (σ): The reciprocal of resistivity.

→ Resistor: The material which offers resistance to the motion of electrons.

→ Overloading (or): When the current drawn from the mains is more than 20 A, Short circuit overheating occurs and may cause a fire. This is called overloading.

→ Fuse: The fuse consists of a thin wire of a low melting point.

→ Semi-conductors: The materials whose resistivity is 10⁵ to 10¹⁰ times more than that of metals and 10¹⁵ to 10¹⁶ times less than that of insulators.
Eg: Silicon, Germanium.

→ Conductors: The materials which can conduct electricity.

→ Insulators: The materials which can’t conduct electricity.

→ Sir Charles Wheatstone(1802 – 1875):

• Sir Charles Wheatstone was a professor in London. He was very famous for his telegraph and stereoscope.
• He discovered the principles of stereoscopic vision and invented the stereoscope.
• His name is attached to the circuit he invented for the newly invented telegraph.

Students can go through AP State Board 10th Class Physical Science Notes Chapter 8 Chemical Bonding to understand and remember the concept easily.

AP State Board Syllabus 10th Class Physical Science Notes Chapter 8 Chemical Bonding

→ A chemical bond is an attractive force between two atoms in a molecule.

→ Atoms which contain 8 electrons in the outermost shell are stable and less reactive.

→ Electron transfer occurs from one atom to another because atoms try to acquire an inert gas configuration.

→ Ions are charged particles.

→ The atom which loses electron acquire positive charge and the atoms gain electrons acquire a negative charge.

→ The formation of ionic compounds involves the formation of ions and the attraction of ion pairs.

→ Oxidation involves the removal of electrons.

→ Reduction involves the addition of electrons.

→ Oxidation and reduction go side by side.

→ The compounds containing molecules that are formed by sharing of electrons are known as covalent compounds.

→ Covalent compounds are soft with low melting and boiling points.

→ Molecules having two oppositely charged poles are called polar molecules.

→ Vander Waal’s forces are purely electrostatic forces operating between molecules at a short distance.

→ A dipolar molecule attracting announcer dipolar molecule is called dipole-dipole attraction.

→ A strong bond is formed by the maximum overlap of orbitals.

→ End-end overlap of orbitals leads to the formation of sigma (σ) bond and part overlap of orbitals leads to the formation of pi (π) bond.

→ a bond is stronger than an π bond.

→ σ (Sigma) bond exists independently.

→ π bond has no independent existence. It exists only in the presence of a sigma bond.

→ In a double bond one, a and one π bond are present.

→ In a triple bond, one d and two π bonds are present.

→ s – s overlap is present in H₂.

→ p – p overlap is present in F₂, Cl₂, Br_2, and I₂.

→ s – p overlap is present in HF, HC/, HBr, and HI.

→ Molecules having single bonds have only o bonds.

→ Molecules having a single bond are H₂, F₂, Cl₂, Br₂, I₂, BeCl₂, etc.

→ Molecules having double bonds are O₂, C₂H₄, CO₂, etc.

→ C₂H₂, IM₂, HCN, CaC₂, etc. have triple bonds.

→ The number of valence electrons available in the atoms decides the type of bond.

→ To explain the bond angles in the molecules through covalent bonds the Valence – Shell – Electron – Pair – Repulsion – Theory (VSEPR).

→ VSEPR was proposed by Sidgwickand Powell (1940). It was further improved by Gillespie and Nyholm (1957).

→ Electrons: Elementary particles in an atom with a negative charge.

→ Noble gases: A group of monoatomic gaseous elements forming group ‘O’ of the periodic table.

→ Lewis dot structure: The valence electrons in the atom of an element are depicted in a short form by Lewis symbol or Lewis dot structure.

→ Octet rule: A stable group of eight electrons in the outer shell of an atom is called the octet rule.

→ Chemical bond: The force of attraction between any two atoms or a group of atoms that results in a stable entity is called a chemical bond.

→ Ionic bond: The electrostatic attraction force that keeps cation and anion together to form a new electrically neutral compound is called ‘Ionic bond’.

→ Covalent bond: The chemical bond formed between two atoms by mutual sharing of a pair of valence shell electrons so that both of them can attain octet or duplet in their valence shell is called the covalent bond.

→ Cation: It is a positively charged ion formed by the removal of an electron from an atom.

→ Anion: It is a negatively charged ion formed by the addition of an electron to the atom.

→ Electrostatic force: Force of attraction between positively charged and negatively charged bodies or ions is called electrostatic force.

→ Electrovalent: The valence concept has been explained in terms of electrons. It is also called electrovalent.

→ Polar solvent: Polar solvents are the compounds such as water and liquid ammonia which have dipole moments and consequently high dielectric constants. The solvents are capable of dissolving ionic compounds or covalent compounds that ionize.

→ Non-polar solvent: Non-polar solvents are compounds such ethane and benzene, which do not have dipole moments. These do not dissolve in but will dissolve nonpolar covalent compounds

→ Formation of molecules: Atoms combine and form molecules. This is called the formation of molecules.

→ Ionic compounds: The compounds formed by the ionic bonds are called compounds.

→ Covalent compounds: The compounds formed by the covalent bonds are covalent compounds.

→ Electropositive character: The ability to lose electrons and become a positively charged ion of an atom is called the electropositive character.

→ Electronegative character: The tendency of an atom to gain electrons and become a negative ion.

→ Polar bonds: These are formed due to unequal sharing of electrons by the combining atoms.

→ Bonded pair of electrons: Electrons which arranged by atoms to share and form a bond is called bonded pair of electrons.

→ Lone pair: Unshared electron pair or non-bonding electron pair.

→ Bond length: Bond length or bond distance is the equilibrium distance between the nuclei of two atoms that form a covalent bond.

→ Bond energy: An amount of energy associated with a bond in a chemical compound.

→ The shape of the molecules: While atoms combine and form molecules they should have some shape. They are called the shape of the molecules.

→ Linear: A molecule in which the atoms are in a straight line as in carbon dioxide O = C = O.

→ Tetrahedral: Having four faces.

→ Properties of Ionic and: Formula mass, physical appearance, type of bond, covalent compounds melting point, boiling point, solubility, etc.

→ Configuration: The arrangement of electrons around the nudes in an atom.

→ Oxidation: The process in which an atom, ion, or molecule loses electrons.

→ Conductivity: Covalent compounds are poor conductors of electricity due to rigid bonding.

→ Van der Waal forces: Van der Waal forces are purely electrostatic forces operating between molecules at a short distance.

→ Dipole – dIpole forces: A dipolar molecule attracting another dipolar molecule.

→ Banana bond: Informal name for the type of electron-deficient bond holding the B – H – B bridges in boranes and similar compounds.

→ Bivalent or divalent: Having a valency of two.

→ Bisulfate: Hydrogen sulfate.

→ Alkali: A base that dissolves in water to give hydroxide ions.

→ Atom: The smallest part of an element that can exist chemically.

→ Single bond: Covalent bonds in which one pair of electrons is shared are known as covalent ‘single bond’.

→ Double bond: Covalent bonds in which two pairs of electrons are shared are known as covalent ‘double bonds’.

→ Triple bond: Covalent bonds in which three pairs of electrons are shared are known as covalent ‘triple bonds’.

→ Compound: A substance formed by the combination of elements in fixed proportions.

→ Dissociation: The breakdown of a molecule, ion, etc. into smaller molecules, ions, etc.

→ Electronegativity: It is the ability of the bonded atom to attract the electron density of the shared electrons.

→ Count Alessandro Volta (1745 – 1827):

• Volta was born in Como, Italy to a noble family.
• He made discoveries In electrostatic, meteorology, and pneumatics.
• His most famous invention, however, is the first battery (cell).
• Volta’s battery was later refined by other scientists and the French emperor, Nepolean, made volta a TMCount” for his discovery.

Students can go through AP State Board 10th Class Physical Science Notes Chapter 7 Classification of Elements- The Periodic Table to understand and remember the concept easily.

AP State Board Syllabus 10th Class Physical Science Notes Chapter 7 Classification of Elements- The Periodic Table

→The group of three elements in ascending order of their atomic weights in which the molecular weight of a middle element is the average of the first and third element is called a triad.

→ Elements are arranged in ascending order of their atomic weights, then every eighth element from starting element has similar properties. This is called an octave.

→ The horizontal rows and vertical columns of a periodic table are called periods and groups respectively.

→ The systematic arrangement of elements in a table in horizontal rows and vertical columns is called a periodic table.

→ Mendeleev’s periodic law: The physical and chemical properties of the elements are periodic functions of their atomic weights.

→ Atomic weight = Equivalent weight × valency.

→ Moseley’s periodic law: The physical and chemical properties of elements are periodic functions of their atomic numbers.

→ If differentiating electron enters s sub-shell, they are called s-block elements.

→ If differentiating electron enters p, d, and f shells they are called p-block, d-block, and f-block elements respectively.

→ The Group of elements is called the element family or chemical family.

→ Elements having atomic numbers 58 to 71 are called lanthanides.

→ Elements having atomic numbers 90 to 103 are called actinides.

→ Metalloids or semi-metals are elements that have properties that are intermediate between the properties of metals and non-metals.

→ Elements are classified on the basis of similarities in their properties.

→ Dobereiner grouped the elements into Triads and Newlands gave the law of octaves.

→ Modern periodic law: The physical and chemical properties of the elements are periodic functions of their electronic configurations.

→ Anomalous in the arrangement of elements based on increasing atomic mass could be removed when the elements were arranged in order of increasing atomic number, a fundamental property of the element discovered by Moseley.

→ Elements in the modern periodic table are arranged in 18 groups and 7 periods.

→ Elements are classified into s, p, d, f blocks depending upon which sub-shell the differentiating electron enters in the atom of the given element.

→ All the d-block elements (except the Zn group) are known as transition elements and all the f-block elements (both Lanthanides, Actinides) are known as inner transition elements.

→ Half of the distance between nuclei of two atoms in solids is called atomic size.

→ Atomic size is measured in a picometer.
1 pm = 10^-12 m.

→ Atomic radii of metals are called metallic radii.

→ The half of the distance between the two atoms in a covalent molecule is called the covalent radius.

→ The size of the positive ion is less than the neutral atom.

→ The size of the negative ion is greater than the neutral atom.

→ The energy required to remove an electron from the outermost orbit or shell of a neutral gaseous atom is called ionization energy (or) first ionization energy.

→ The energy required to remove the electron from unipositive ion is called 2nd ionization energy.

→ The electron affinity of an atom is defined as the energy liberated when an electron is added to its neutral gaseous atom.

→ The energy liberated when an electron is added to a uni-negative ion is called the 2nd electron affinity of that element.

→ The relative tendency of its atom to attract electrons towards itself when it is bounded to the atom of another element is called electronegativity of the element.

→ Triad: A group of three elements in which the atomic weight of a middle element is the average of first and third elements with similar properties.

→ Octave: When elements are arranged in the ascending order of their atomic weight, every element starting from a given element resembles in its properties to that of the starting element are called octaves.

→ Periodic Law: Law that regards the properties of elements in the periodic table.

→ Periodic table: The charts of elements arranged ¡n a systematic order of increasing order of atomic weight or atomic number is called periodic table,

→ Periods: The horizontal rows in the periodic table are called periods.

→ Groups: The vertical columns in the periodic table are called groups.

→ Lanthanides: Elements from ₅₈Ce to ₇₁Lu possess almost the same properties as ₅₇La. So they are called lanthanides.

→ Actinides: Elements from ₉₀Th to ₁₀₃Lr are called actinides.

→ Element family: The elements that belong to the same group in the periodic table having similar properties are called element families.

→ Metalloids: The elements which have both metallic and non-metallic properties are called metalloids.

→ Periodicity: The properties of elements in a group of a periodic table have similar properties, that is called periodicity.

→ Atomic radius: The half of distance between two nuclei in solids and half of distance between two atoms participated in a chemical bond. Simply we can give the distance between the nucleus and outermost orbital.

→ Ionization energy: The energy required to remove an electron from the outermost orbit or shell of a neutral gaseous atom is called ionization energy.

→ Electron affinity: The electron affinity of an element is the energy liberated when an electron is added to a neutral gaseous atom.

→ Electronegativity: The relative tendency of the element of an atom to attract electrons towards itself when it is bonded to another atom of another element.

→ Electropositivity (or): The tendency of metals to lose electrons is called Electro- Electropositive character positive character.

→ Mendeleev’s periodic law: The properties of elements are the periodic functions of their atomic weights.

→ Modern periodic law: The properties of elements are the periodic functions of their atomic numbers.

→ Alkali metal family: Group IA elements are called the alkali metal family.

→ Alkali earth metal family: Group lIA elements are called the alkali earth metal family.

→ Chalcogen family: The elements in group (16) form ores with elements.

→ Noble gases: The elements of the group (18) (VIII-A) which are least active.

→ Electron gain enthalpy: Electron affinity of the element is also called electron gain enthalpy.

→ Transition elements: d-block elements are called transition elements.

→ Inner transition elements: Lanthanoids and Actinoids (f block elements) are called inner transition elements.

→ Metallic radius: Half of the distance between adjacent nuclei of atoms in solid.

→ Covalent distance: Half of the distance between atoms in a covalent bond.

→ Valence (or) Valency: The combining power of elements with respect to hydrogen or oxygen.

→ Metals: The elements with three or fewer electrons in the outer shell are called metals.

→ Non-metals: The elements with five or more electrons in the outermost shell are called non-metals.

→ Pico meter: The unit of atomic size.
1 pm = 10^-12 m.

→ Dmitri Ivanovich Mendeleev (8 Feb. 1834 – 2 Feb. 1907):

• Dmitri Ivanovich Mendeleev was a Russian chemist and Inventor.
• He formulated periodic law, created his own version of the periodic table of elements.
• He used the periodic table to correct the properties of some already discovered elements.
• And also predict the properties of elements yet to be discovered

Students can go through AP State Board 10th Class Physical Science Notes Chapter 6 Structure of Atom to understand and remember the concept easily.

AP State Board Syllabus 10th Class Physical Science Notes Chapter 6 Structure of Atom

→ Light can be characterized by its wavelength and frequency (v) and these quantities related to the speed of light as c = vλ

→ A spectrum is a group of wavelengths.

→ Electromagnetic energy (light) can have only certain discrete energy values which are given by the equation E = hv.

→ Electrons in an atom can gain energy by absorbing a particular frequency of light and can lose energy by emitting a particular frequency of light.

→ Bohr’s model of an atom: Electrons are present in stationary states. The electron moves to a higher energy level If it absorbs energy in the form of electromagnetic energy or moves to a lower energy state by emitting energy in the form of electromagnetic energy of appropriate frequency.

→ Atomic line spectra arise because of the absorption/emission of certain frequencies of light energy.

→ It is not possible to measure the position and velocity of an electron simultaneously.

→ The space around the nucleus where the probability of finding electrons is maximum is called orbital.

→ The three quantum numbers n, l, m describe the energy, shape and orientation respectively of an atomic orbital.

→ Spin is an intrinsic property of an electron.

→ The arrangement of electrons in shells, sub-shells and orbitals in an atom is called the electron configuration.

→ According to Pauli’s exclusion principle, no two electrons of the same atom can have the entire four quantum numbers same.

→ Aufbau principle: The lowest energy orbitals are filled first.

→ Hund’s rule: The orbitals of equal energy (degenerate) are occupied with one electron each before the pairing of electrons starts.

→ As long as an electron revolves in a stationary orbit it neither loses nor gains energy.

→ A rainbow is a natural spectrum appearing in the sky.

→ Light is considered an electromagnetic wave.

→ Electromagnetic waves are produced when an electric charge vibrates.

→ The electromagnetic wave has a speed of light, i.e. 3 × 10⁸ ms^-1.

→ The relation between frequency and velocity of light is c = vλ.

→ An atom or molecule having the lowest possible energy is said to be in-ground state otherwise it is said to be in an excited state.

→ An atom or molecule in an excited state can emit light to lower its energy in order to get stability.

→ Sodium vapour lamp emits light of the wavelengths 589.0 nm to 589.6 nm.

→ Line spectrum is also known as discrete spectrum.

→ The atomic spectrum of a hydrogen atom is a line spectrum.

→ Stationary states are also called energy levels.

→ Sommerfeld proposed elliptical orbits.

→ The Quantum mechanical model of an atom was developed by Erwin Schrodinger.

→ The principal quantum number explains the size.

→ As n increases, the orbitals become larger and the electrons in those orbitals are farther from the nucleus.

→ The number of electrons in a shell is 2n².

→ Orbital quantum number (l) gives the shape of the orbital.

→ l takes values from 0 to n – 1.

→ The splitting of spectral lines in a magnetic field is called the Zeeman effect.

→ The splitting of spectral lines in an electric field is called the Stark effect.

→ The orientation of the orbital with an external magnetic field determines the magnetic orbital quantum number.

→ The magnetic orbital quantum number takes values from – l to l.

→ Orbitals of the same energy are called Degenerate orbitals.

→ Wave: Surging movement of water, electricity, etc.

→ Spectrum: A spectrum is a group of wavelengths or frequencies.

→ Intensity: The amount of energy per unit volume is called intensity.

→ Discrete energy: Definite energy s called discrete energy.

→ Line spectrum: The colours correspond to certain discrete wavelengths of light and are called Line spectrum. It Is also known as discrete spectrum.

→ Orbital: The region of space around the nucleus where the probability of finding an electron is maximum is called an orbital.

→ Quantum numbers: The numbers indicate the probability of finding the electron in the space around the nucleus.

→ Shell (or) orbit: The path of an electron around the nucleus is called shell or orbit.

→ Sub-shells: Atomic orbitals are also called sub-shells.

→ The shape of orbital electron spin: Electron has two types of spins. One is clockwise spin and the other is anti-clockwise spin,

→ Electronic configuratIon: The distribution of electrons in various atomic orbitals called electronic configuration.

→ Pauli’s exclusion principle: No two electrons of the same atom can have all four quantum numbers the same.

→ Aufbau principle: The electrons should be placed in the lowest available orbital until the total number of electrons added is equal to the atomic number.

→ Hund’s rule: This rule states that electron pairing in orbitals starts only when all available empty orbitals of the same energy are singly occupied.

→ Dispersion: The splitting of light into different colours (VIBGYOR) is called dispersion.

→ Electromagnetic wave: When an electric field and magnetic field are perpendicular to each other and at right angles to the direction of propagation of the wave is formed. Such a wave is called an electromagnetic wave.

→ Electromagnetic spectrum: The entire, range of electromagnetic wave frequencies is known as the electromagnetic spectrum.

→ Emission spectrum: When a light beam emitted by a source ¡s dispersed to get the spectrum Is called an emission spectrum.

→ Continuous spectrum of emission: When light is dispersed from a source spectrum of continuously distributed colours is obtained on a dark background is called a continuous spectrum of emission.

→ Line spectrum of emission: When a light ¡s dispersed with a sharp bright line on a dark background, such a spectrum is called a tine spectrum of emission.

→ Stationary orbits: Orbits of fixed energy are called stationary orbits of energy levels.

→ Heisenberg’s Principle of Uncertainty: It is not possible to find the exact position and velocity of an electron simultaneously and accurately.

→ Principal Quantum Number (n): The quantum number which explains the size and energy of orbitals is called principal quantum number.

→ Angular Momentum Quantum Number (l): The quantum number which defines the shape of the orbital occupied by the electron and the orbital angular momentum of the electron in motion (m).

→ Magnetic orbital quantum number (m_l): The orientation of orbital with an external magnetic field determines the magnetic orbital quantum number.

→ Spin quantum number (s): It gives spin of the electrons about their own axis.

→ c = vλ: The frequency (v), wavelength (λ) and velocity of light (c) related as follows c = vλ

→ E = hv: Electromagnetic energy can have only certain discrete energy values which is given by the equation E = hv where h = Planck’s constant
v = frequency of radiation

→ Visible spectrum: The spectrum which visible to our eyes s called the visible spectrum.

→ Duplet configuration: ns² configuration is called duet configuration.

→ Octet configuration: If the element has eight electrons in the outermost orbital, It is called Octet configuration.

→ Zeeman effect: Splitting of spectral lines in a magnetic field is called the Zeeman effect.

→ Stark effect: Splitting of spectral lines In electric field Is called Stark effect.

→ Degenerate orbitals: OrbitaIs of the same energy is called degenerate orbitals.

→ Prince Louis Victor DeBroglie:

• de Broglie, a French theoretical physicist born in 1892, received the Nobel Prize in 1929 ¡or his work on the wave nature of electrons.
• He proposed dual nature 01 electron which is very much used in the determination of characterisation 01 electron and structure 0f atom.
• He gave the wavelength (λ) material wave as I = \(\frac{\mathbf{h}}{\mathbf{m v}}\)

→ Neils Henrik David Bohr

• Neils Henrik David Bohr was a Danish physicist.
• He made foundational contributions to understanding atomic structure and quantum theory.
• He received the Nobel Prize in Physics for those foundational contributions in 1522.
• Bohr was also a philosopher and a promoter.

→ Max Karl Ernst Ludwig Planck:

• Max Karl Ernst Ludwig Planck was a German theoretical physicist.
• He originated quantum theory, which won him the Nobel Prize n Physics in 1918.
• Planck made many contributlon6 to Theoretical physics, but his lame rests primarily on his role as originator of the quantum theory.
• This theory revolutionized human understanding of atomic and subatomic processes.

Students can go through AP State Board 10th Class Physical Science Notes Chapter 5 Human Eye and Colourful World to understand and remember the concept easily.

AP State Board Syllabus 10th Class Physical Science Notes Chapter 5 Human Eye and Colourful World

→ The human eye uses light and enables us to see the object. It has a lens in its structure.

→ The eye is a natural optical device using which a human being could see objects around him. It forms an inverted, real image on a light-sensitive surface called the retina.

→ The minimum distance at which objects can be seen most distinctly without strain is called the least distance of distinct vision (or) distance of clear vision.

→ The range of vision of human beings is 25 cm to infinity.

→ The minimum distance between the objects and the eye so that a clear image is formed on the retina is called the least distance for clear vision or near the point of the eye. This distance is 25 cm for the human eye.

→ Rods and cones are the cells in the retina which are light sensitive. Rods respond to the intensity of light. Cones respond to the illumination.

→ There are 125 million cells – rods and cones. The cells generate signals which are transmitted to the brain through the optical nerves.

→ The retina is the light-sensitive surface of the eye in which an image is formed. It is equivalent to the photographic film in a camera. It contains rods and cones.

→ The ability of the ciliary muscles to adjust the curvature and thereby the focal length to get a clear view of objects is called accommodation.

→ The maximum distance between the objects and the eye so that a clear image is formed on the retina is called the near the point of the eye also.

→ The maximum angle, at which we are able to see the whole object is called the angle of vision.

→ The angle of vision for a healthy human being is about 60°. It varies from person to person and with age.

→ The value of the minimum distance of clear vision is about 25 cm.

→ The eyeball is nearly spherical in shape.

→ The farthest point up to which the eye can see objects clearly is called the far point of the eye. For a normal eye, it is infinity.

→ The maximum variation in the power of the lens so that, the far-off and nearby objects are viewed is called the power of accommodation. For a person having normal vision, it is about 4 diopters.

→ The time for which the impression or sensation (of an object) continues in the eye is called the persistence of vision. It is about \(\frac{1}{16}\)th part of a second.

→ The motion picture is done to create a clear impression of an event. The event is projected at the rate of 24 frames per second.

→ Cones with specific colours are in the retina. If some cones are absent, the distinction of colours is not possible. In such a case, the process is said to be colour blind.

→ Some persons have difficulty seeing the objects in dim light during the night. This defect of the eye is called night blindness.

→ A person with myopia can see nearer objects clearly but cannot see distant objects clearly.

→ Myopia (or) nearsightedness is caused by

• excessive curvatures of the eye|
• elongation or increase in the size of the eye lens.

It can be corrected by using spectacles with a concave lens of suitable focal length.

→ A person with hypermetropia (farsightedness) can see distant objects clearly but cannot see nearer objects distinctly.

→ Hypermetropia is caused by

• increase in the focal length of the eye lens
• shortening or decrease in the size of the eye lens.

It is corrected by using spectacles made from convex lenses of suitable focal lengths.

→ Most of the old persons suffer from long-sightedness. In this defect, the power of accommodation of the eye decreases with ageing.

→ The phenomenon of the splitting of white light into component colours when passing through a glass prism is called dispersion of light.

→ The band of colour components of a light beam obtained on a white screen when white light passes through a prism is called the spectrum.

→ A rainbow is a natural spectrum of sunlight in the form of bows appearing in the sky when the sun shines on raindrops after the rain. The raindrops act like small prisms.

→ When the light rays pass through the atmosphere having layers of different densities and refractive indices, then refraction of light takes place. This refraction of light by the earth’s atmosphere is called atmospheric refraction.

→ Scattering of light is a phenomenon of change in the direction of light on striking a particle like an atom, a molecule, dust particles, water droplets, etc. It explains phenomenon like ‘blue colour of the sky’ the reddening of the sun at sunrise and sunset, etc.

→ The bending of light passing through the earth’s atmosphere is called atmospheric refraction.

→ As we move about the surface of the earth, the density of air goes on decreasing.

→ Light travels from rarer to denser medium. Rays always bend towards the normal.

→ Stars twinkle on account of atmospheric refraction.

→ Sun appears to rise two minutes earlier and two minutes later due to the atmospheric refraction.

→ Very small particles scatter light of a shorter wavelength better than a longer wavelength.

→ The scattering of longer wavelengths of light increases as the size of the particles increases.

→ Longer particles scatter light of all wavelengths.

→ The refractive index of prism (n) = \(\frac{\sin \left[\frac{(A+D)}{2}\right]}{\sin \frac{A}{2}}\)

→ Sir C.V. Raman explained the phenomenon of scattering in gases and liquids.

→ Raman found experimentally that the frequency of scattered light by the liquids is greater than the frequency of incident light. This is called Raman Effect.

→ By using the Raman effect scientists determine the shapes of the molecules.

→ The formula for the speed of the wave (v) = Frequency (v) × Wavelength (λ)

→ Least distance of distinct vision: The minimum distance of the near object (point) from the eye for clear vision without strain is called the least distance of distinct vision.

→ The angle of vision: The maximum angle at which we are able to see the whole object is called the angle of vision.

→ Accommodation of eye lens: The process of adjusting the focal length of the eye lens is called the accommodation of the eye lens.

→ Myopia: it is the defect of the people who cannot see objects at a long distance is called Myopia.

→ Hypermetropia: The defect of the people who cannot see objects at a near distance is called Hypermetropia.

→ Presbyopia: It is a vision defect when the ability of accommodation of the eye usually decreases with ageing.

→ Power of lens: It is the reciprocal of focal length.
Power of lens (P) = \(\frac{1}{f(\text { in } m)}\) (or) P = \(\frac{100}{f(\text { in } cm)}\)

→ Prism: A block of glass or other transparent material usually having triangular bases. Prisms have several uses in optical systems.
(OR)
A polyhedron with two parallel congruent polygons as bases and parallelograms for all other faces. A triangular prism has triangular bases.

→ The angle of prism or Refracting angle of prism: The angle between the two refracting of the prism surfaces.
(OR)
The angle between the two refracting surfaces of the prism is called the angle (or) refracting angle of the prism.

→ The angle of minimum: The angle between the incident ray and emergent ray is deviation called the angle of deviation. The lowest deviation produced by a prism in the i-d graph is called the angle of minimum deviation.

→ Dispersion: The splitting of white light into colours (VIBGYOR) when it passes through prism ¡s called dispersion.

→ Scattering: Atoms or molecules which are exposed to light absorb light energy and radiate some part of the light energy in different directions. This process is called scattering.

→ Scatter: Spread; go in various directions.

→ Vision: Sight

→ Medium: A substance through which light passes. Ex: air, glass, etc.

→ Luminous body: The bodies which emit light and act as a source of light.

→ Erect: Upright

→ Focal length (f): The distance between the pole of the mirror and principal focus.

→ Refraction: Bending of light rays at the refracting surface when the light travels from one medium to other.

→ Non-luminous object: An object that does not give out light of its own.

→ Transparent: A material that allows the light falling on it to pass through.

→ Translucent: A material that allows only some of the light falling on it to pass through.

→ Opaque: A material Ch dc not allow any light to pass through It.

→ Galileo Galilei (1564 – 1642):

• Galileo Galilei was born in Puja, ItaIy in 1564.
• He invented the tripod microscope, built a telescope.
• While gazing through the telescope, Galileo observed and drew what he saw. The moons phases, the milky way, clusters of stars and phenomena that seemed to confirm his idea that the Earth was not the centre of the universe. Contrary to the popular Ptolemaic system, Galileo hypothesized that the Earth was one of many heavenly bodies that comprise our solar system.
• Although Galileo Is remembered for both of his experiments with gravity and for his astronomical observations, his invention of the telescope is probably his most significant contribution.
• Other significant areas of Galileo’s influence include mechanics, microscopy and magnetism.

Students can go through AP State Board 10th Class Physical Science Notes Chapter 4 Refraction of Light at Curved Surfaces to understand and remember the concept easily.

AP State Board Syllabus 10th Class Physical Science Notes Chapter 4 Refraction of Light at Curved Surfaces

→ The lens is an optical system with two refracting surfaces.

→ The lens which is thicker at its centre than edges is called a convex (or) converging lens.

→ The lens which is thicker at its edges than the centre is called a concave (or) diverging lens.

→ The lemon in the water of the glass tumbler appears bigger than its actual size when viewed from the sides of the tumbler due to refraction.

→ The relation between refractive indices of media, object distance, image distance and radius of curvature is given by
\(\frac{n_{2}}{v}-\frac{n_{1}}{u}=\frac{\left(n_{2}-n_{1}\right)}{R}\)

→ In the case of plane surfaces, R & f are infinity. Power is equal to zero.
∴ \(\frac{n_{2}}{v}=\frac{n_{1}}{u}\)

→ Each curved surface of a lens is part of a sphere.

→ The centre of the sphere which contains the part of the curved surface is called the centre of curvature.

→ The midpoint of the lens is called a pole (or) optical centre.

→ The point from which rays seem emanating is called focal point or focus (F). (or) The point where rays converge is called the focal point of focus.

→ Every lens has two focal points.

→ The distance between the focal point and pole is called focal length which is denoted by f.

→ The line that joins the centre of curvature and the pole is called the principal axis.

→ The distance between the centre of curvature and pole is called the radius of curvature (R).

→ Any ray passing through the principal axis is un-deviated.

→ Any ray passing through the pole is also un-deviated.

→ The rays passing parallel to the principal axis converge at focus or diverge from focus.

→ The ray passing through the focus of the convex lens will take a path parallel to the principal axis after refraction.

→ When parallel rays fall on the lens making a certain angle with the principal axis the rays converge at a point or appear to diverge from a point lying on a focal plane.

→ If the size of the image is larger than that of an object, it is called a magnified image.

→ Lens formula is \(\frac{1}{v}-\frac{1}{u}=\frac{1}{f}\)
v = image distance
u = object distance
f = focal length.

→ Lens maker formula is \(\frac{1}{f}\) = (n -1)\(\left(\frac{1}{R_{1}}-\frac{1}{R_{2}}\right)\)
n is the absolute refractive index
R₁ R₂ are radii of curvature.

→ Lens: A lens is formed when a transparent material is bounded by two spherical surfaces.

→ Focal Length (f) The distance between the focal point and optic centre (pole) is called the focal length of the lens. It is denoted by f.

→ Focus (F): The point of converging lar) the point from which rays seem emanating is called focal point or focus.

→ The optic centre or Pole (P): The midpoint of a thin lens is called a pole or optical centre.

→ Principal axis: The line joining the centre of two curved surfaces is called the principal axis
(or)
The line joining the centre of curvatures and the pole.

→ The radius of curvature (R): The distance between the centre of curvature and the optic centre is called the radius of curvature.

→ Centre of curvature (C): The centre of the sphere which contains the part of the curved surface is called the centre of curvature.

→ Focal plane: A plane that is perpendicular to the principal axis at the focus is called the focal plane.

→ Beam: A number of rays combined together are called a beam.

→ Ray: The straight-line path along which the light travels, in a homogeneous medium, is called a ray.

→ Convergent beam: When a group of light rays fall on a convex lens after refraction meets at a point is called a convergent beam.

→ Divergent beam: When a group of light rays fall on a concave lens after refraction move away from a point is called a divergent beam.

→ Parallel beam: When a group of light rays parallel to each other is called a parallel beam.

→ Real image: The image formed on the screen is called a real image.

→ Virtual image: The ¡mage which cannot be formed on the screen is called a virtual image.

→ Aperture: The effective width of a lens through which refraction takes place ¡s called the aperture.

→ Magnifying glass: A glass, which enlarges an object.

→ Biconvex or Double convex lens: A lens that may have two spherical surfaces bulging outwards is called a double convex lens.

→ Biconcave or Double concave Pens: It is bounded by two spherical surfaces curved inward.

→ Lens formula: \(\frac{1}{\mathrm{v}}-\frac{1}{\mathrm{u}}=\frac{1}{\mathrm{f}}\)
v = image distance
u = object distance
f = focal length of tens

→ Lens maker’s formula: \(\frac{1}{f}\) = (n -1)\(\left(\frac{1}{R_{1}}-\frac{1}{R_{2}}\right)\)
n = Absolute refractive index
R₁ = Radius of curvature of the first surface
R₂ = Radius of curvature of the second surface

→ Enlarged image (Magnified image): If the size of the image is greater than that of an object, it is called an enlarged (or) magnified image.

→ Diminished image: If the size of the image is less than that of an object, it Is called a diminished Image.

→ Object distance (u) : Distance between object and lens (optic centre).

→ Image distance (v) : Distance between image and lens (optic centre).

→ Sir David Brewster (11 Dec. 1781 – 10 Feb. 1868):

• Sir David Brewster was a Scottish physicist, mathematician, astronomer, inventor, writer, historian of science.
• Most noted for his contributions to the field of optics.
• He studied the double refraction by compression and discovered the photoelastic effect.
• William Whewell dubbed him the ‘Father of modern experimental optics and ‘The Johannes Kepler of optics’.
• He Is well recognized by the Inventor of Kaleidoscope and stereoscope.

Students can go through AP State Board 10th Class Physical Science Notes Chapter 3 Refraction of Light at Plane Surfaces to understand and remember the concept easily.

AP State Board Syllabus 10th Class Physical Science Notes Chapter 3 Refraction of Light at Plane Surfaces

→ The process of changing speed when light travels from one medium to another medium is called the refraction of light.

→ Absolute refractive index = \(\frac{\text { Speed of light in vacuum }}{\text { Speed of light in medium }}\) ⇒ n = \(\frac{\mathrm{c}}{\mathrm{v}}\)

→ Relative refractive index, n₂₁ = \(\frac{v_{1}}{v_{2}}=\frac{n_{2}}{n_{1}}\)

→ Snell’s law is given by, n₁ sin i = n₂ sin r.

→ The angle of incidence at which the light ray travels from denser to rarer medium grazes along the interface is called the critical angle of that interface.
sin C = \(\frac{n_{2}}{n_{1}}\)
where n₁ is the refractive index of the denser medium and n₂ is the refractive index of the rarer medium.

→ If the angle of incidence is greater than the critical angle, the light ray is reflected into the denser medium at the interface. This phenomenon is called total internal reflection.

→ Example of denser medium: Glass.

→ Example of a rarer medium: Air.

→ When the light travels from rarer to a denser medium, it bends towards the normal.

→ When the light travels from a denser to a rarer medium, it bends away from the normal.

→ Optical fibers work on the principle of total internal reflection.

→ Mirages are formed due to total internal reflection.

→ The refractive index increases with height.

→ Total internal reflection is the main cause for the brilliance of diamonds.

→ Light travels at a speed of 3 × 10⁸ m/s.

→ The Refractive index depends on the following factors :

• Nature of material
• The wavelength of light used.

→ When the refractive index of glass is \(\frac{3}{2}\), then the speed of light in glass is equal to 2 × 10⁸ m/s.

→ Laws of refraction :

1. The incident ray, the refractive ray, and the normal interface of two transparent media at the point of incidence lie in the same plane.
2. During refraction, the light follows Snell’s law.

→ A coin kept at the bottom of a vessel filled with water appears to be raised and a lemon kept in the water of glass tumbler appears to be bigger than its size due to refraction of light.

→ Fermat’s principle states that the light ray always travels in a path that needs the shortest possible time to cover the distance between the two points.

→ Speed of light changes at the interface of two media.

→ The angle between the incident and normal ray is called the angle of incidence.

→ The angle between normal and refracted ray is called the angle of refraction.

→ The angle between normal and emergent rays is called the angle of emergence.

→ The formation of mirage is the best example where the refractive index of a medium varies throughout the medium.

→ Refraction: The process of changing speed when light travels from one medium to another is called the refraction of light.

→ Incident ray: The ray which is an incident on a surface is called an incident ray.

→ Refracted ray: The ray which refracted from a surface is called refracted ray.

→ The angle of Incidence: The angle between the incident ray and normal ray is called the angle of incidence.

→ The angle of Refraction: The angle between refracted ray and normal ray is called the angle of refraction.

→ Absolute refractive index: The ratio of the speed of light in a vacuum to the speed of light in the medium.

→ Relative refractive index: It is the ratio of the refractive index of the second medium to the refractive index of the first medium.

→ Snell’s law: It is the ratio of the sine of the angle of incidence to the sine of the angle of refraction.

→ Critical Angle: The angle of incidence at which the light ray travels from denser to rarer medium grazes along the interface is called the critical angle of that interface.

→ Total internal reflection: When the angle of incidence is greater than the critical angle, the light ray is reflected into the denser medium at the interface. This phenomenon is called total internal reflection.

→ Mirage: Mirage is an optical illusion where it appears that water is collected on the road at a distant place but when we get there, the road is dry.

→ Shift: The distance between incident and emergent parallel rays is called shift.

→ Optical Fibre: An optical fiber is a very thin fiber made of glass (or) plastic having a radius of about a micrometer (10^-6 m).

→ Medium: A substance through which light passes is called medium. The medium has more optical density.

→ Denser Medium: The medium which has less optical density.

→ Interface: A point where two things meet and interact is called an interface.

→ Fermat’s principle: The light ray always travels in a path that needs the shortest possible time to cover the distance between the two given points.

→ The angle of emergence: The angle between normal and emergent rays is called the angle of emergence.

→ Light pipe: A bunch of optical fibers is called a light pipe.

→ Mass density: Mass per unit volume is called mass density.

→ Ray: The straight-line path along which the light travels in a homo¬geneous medium is called a ray. It is represented by an arrowhead on a straight line, the arrowhead gives the direction of propagation of light.

→ Beam: A number of rays combined together are called a beam

Williboard Snell Van Royen (1580 – 1626):

• He was a Dutch astronomer and mathematician.
• His name has been attached to the law of refraction of light.
• In 1815, he planned and carried into practice a new method of finding the radius of the earth by determining the distance of one point from the parallel of latitude of another by means of triangulation.
• He was famous for bis Snell’s law related to the refraction of light.