PSEB Notes

This PSEB 10th Class Social Science Notes Geography Chapter 2 Land will help you in revision during exams.

PSEB 10th Class Social Science Notes Geography Chapter 2 Land

→ Physiographic Divisions:

• The Himalayas.
• Northern plains.
• The peninsular plateau.

→ Mt. Everest (Sagarmatha) – The highest peak in the world (Sagarmatha) 8848 metres.

→ Kanchenjunga – The highest peak of the Himalayas in India (8598 metres).

→ Anai Mudi:

• The highest peak in peninsular India.
• 2698 metres high.

→ The Himalayas – Three parallel ranges-the greater Himalayas, the lesser Himalayas, and Shiwaliks.

→ Pamir Knot – The roof of the world.

→ Galciers of the Himalays – Baltro and Siachen.

→ K2 Godwin Austin – The second highest peak of the world.

→ Passes in the Himalayas – Zoji la, Shipki la, Nathu la, Bomdila.

→ Purvanchal – Patkoi, Naga, Lushai Hills.

→ Sunderbans – Ganga Brahmaputra Delta.

→ Rift valleys – Narmada and Tapi.

→ Guru Shikhar – Highest peak in Aravallies (1722 metres).

→ Central Highlands – Aravavllies, Vindhyas, and Satpuras.

→ Sahyadri – Western Ghats.

→ Deccan trap – N.W. plateau made up of lava.

→ Passes in Western Ghats – Thai ghat, Bhor ghat, Pal ghat.

→ Coastal plain (West) – Konkan, Kanara, Malabar coast.

→ Coastal plain (East) – Coromandel, Utkal coast.

→ Coral islands – Lakshadweep islands.

→ Lagoons (Lakes) – Chilka and Pulicat.

This PSEB 10th Class Social Science Notes Geography Chapter 1 India: An Introduction will help you in revision during exams.

PSEB 10th Class Social Science Notes Geography Chapter 1 India: An Introduction

→ Location – A tropical country.

→ Total Geographical Area – 32, 87, 263 km2

→ Latitudinal extent – 8°4′ North to 37°6′ North.

→ Longitudinal extent – 68°7′ East to 97°25′ East.

→ North-South extent – 3214 km.

→ East-West extent – 2933 km.

→ Land Frontiers – 15,200 km.

→ Coastline – 7,516 km.

→ Standard Meridian – 82½° East longitude.

→ Southernmost point – Indira Point.

→ The southernmost tip of the mainland – Kanyakumari

→ Number of States – 28

→ Number of union territories – 8

→ The Largest State – Rajasthan

→ The Smallest State – Goa.

This PSEB 10th Class Science Notes Chapter 16 Management of Natural Resources will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 16 Management of Natural Resources

→ Our natural resources like forests, wildlife, water, coal, and petroleum need to be used in a sustainable manner.

→ The variety of substances that man gets from earth and nature to meet his basic needs are called natural resources.

→ People’s participation is very important in maintaining the eco-environment.

→ Multicrore project “Ganga Action Plan” to clean and maintain the proper quality of water in the Ganga was launched in 1985.

→ Air, soil, and water are our natural resources.

→ These natural resources should be used in such a way that both resources do not get polluted and the environment remains conserved and pollution-free.

→ Coal and petroleum are also our natural resources and these need to be used in a sustainable manner for development.

→ There is a number of international laws and regulations to protect our environment.

→ Three R’s are being used to save our environment.

→ These three R’s respectively: Reduce (useless), Recycle (Recycle the wastes), Reuse (use things again and again).

→ ‘Reduce’ means that we should use less avoiding unnecessary wastage.

→ Electricity and water can be saved by repairing leaking taps and by switching off lights and fans.

→ ‘Recycle’ means that materials like glass, plastic, metals, etc. can be used again and again by recycling in place of dumping them along with other waste materials.

→ ‘Reusing is better than recycling because a thing can be used again and again.

→ Recycling always needs the consumption of some energy.

→ ‘Ganga Action Plan’ was started in 1985 because the quality of water was reduced to a very low level.

→ Coliform is a group of bacteria and is found in the human intestines.

→ The presence of coliform in water indicates contamination by disease-causing microorganisms.

→ River Ganga runs its course of over 2500 km from Gangotri in the Himalayas to Ganga Sagar in the Bay of Bengal.

→ River Ganga has been turned into a drain by the people living in towns and cities in various states.

→ People wash their clothes at its banks. They pour their garbage and excreta into it. They wash their clothes, take bath, immerse ashes and unburnt corpses in its water.

→ We get energy from the Sun being processed by living organisms and various physical and chemical processes on the earth.

→ The management of natural resources needs a long-termed perspective.

→ Mining also becomes a huge cause of pollution because a large amount of slag is produced due to it.

→ The forests are called “biodiversity hot spots.

→ In any area, one measure of biodiversity is the number of species found there.

→ Forests are the favourite sites for fishing and hunting.

→ We can reduce pressure on the environment by applying the maximum of three R’s (Reduce, Reuse, and Recycle) in our lives.

→ People gather fruits, nuts, and medicines from the forests and they also allow their cattle to graze in the forests. They collect fodder from the forests for their cattle.

→ We get timber, paper, lac, and sports equipment from the forests.

→ Water is a basic necessity for all terrestrial forms of life.

→ Water supports our life system. All chemical reactions of our body take place in the presence of water. It controls the temperature of our bodies. It helps in excretion.

→ Water regulates the atmosphere of our earth. It helps in operating various machines and generating electricity. Water is very necessary for agriculture and industry.

→ Water present in all seas supports aquatic life.

→ Rains in our country are largely due to monsoons.

→ The vegetation cover of our country gets affected because of failure to sustain underground water.

→ In our country, irrigation methods are – dams, tanks, and canals.

→ Large dams and canals were first conceived and implemented by the British in our country.

→ Kulhs were used in Himachal Pradesh for irrigation. This system was evolved about four hundred years ago.

→ Large dams can ensure the storage of adequate water for irrigation and generating electricity.

→ Dams are the obstructions or walls established on the path of river water to collect water in artificial lakes to use for the generation of electricity and irrigation.

→ Check dams are temporary mud walls or permanent walls created to collect water in artificial lakes to recharge underground water.

→ Underground water is important for irrigation and drinking purposes.

→ Building big dams create a lot of problems related to biodiversity, forest area, and displacement of population.

→ In watershed management, soil and water conservation are preferred to increase the vegetation.

→ Fossil fuels like coal and petroleum should be used very carefully because the stocks of these remain very limited under the soil. Also, these cause pollution on burning.

→ Natural Resources: The useful naturally occurring stocks of different substances are termed natural resources.

→ Exhaustible Resources: The resources being destroyed by human activities are called exhaustible resources.
Example: soil, minerals, etc.

→ Inexhaustible Resources: The resources which cannot be exhausted by human activities are called inexhaustible resources.

→ Renewable Resources: The sources of energy which can be replenished are termed renewable resources, e.g. wood, water.

→ Non-renewable Resources: The sources of energy which cannot be replenished and get destroyed after their use are termed as non-renewable resources, e.g. Petroleum, Natural gas, Coal, etc.

→ Underground water: Water is present under the surface of the soil.

→ Pollution. The presence of unwanted, unnecessary, and undesirable changes in biological, physical, and chemical characteristics of the environment is termed pollution. Mainly pollution is of three types – soil pollution, air pollution, water pollution.

→ Recycle: Using products made of plastic, paper, glass, metal, etc. in making new products instead of new material is called recycling.

→ Reuse: It is a simple strategy to use things again and again instead of throwing them away.

→ Water Harvesting: It is a process of capturing used or rainwater in a nearby area to utilize it for our use again and increase the level of underground water.

→ Deforestation: Cutting trees on large scale is called deforestation.

→ Dams: These are the obstructions on the paths of river water to store large amounts of water to be used to generate hydroelectric power and for irrigation purposes.

→ Afforestation: Planting of trees on large scale over a large area.

→ Environmental problem: The problems created by man on the environment by his actions.

→ Biodiversity: Different types of living beings exist in this world. A very large variety of plants and animals are parts of it. Out of these, some are of economic importance. Their structures and usefulness vary. The existence of a wide variety of species living in a particular natural habitat or community is termed biodiversity.

→ Conservation: It is a process to prevent our environment from degradation and to work for its betterment by improving the conditions to stop further deterioration.

→ Ganga Action Plan: A multicrore project proposed by Govt, of India in 1985 to clean river Ganga of its pollutants.

→ Coliform Bacteria: A coliform is a group of gram-negative bacteria that causes many diseases in the human intestines. Its presence in water indicates contamination of disease-causing micro-organisms.

→ 3-R: Reduce, Recycle, Reuse.

→ Wildlife: All types of naturally occurring plants and animals and their species found in nature are termed wildlife. It is neither cultivated nor tamed/domesticated.

→ Ecological Conservation: ‘Ecological Conservation’ is a term used to conserve, nature and natural resources to maintain ecological balance.

→ Water Resources: The resources like rivers, canals, oceans, rains, etc. are called water resources which provide water for our use.

→ Watershed Management: It is the scientific conservation of soil and water to get better and increase biomass production.

→ Water Harvesting: Water harvesting is to capture and save rainwater to make use of it for better purposes.

→ National Park: A very large specified area reserved and dedicated by the government to conserve natural resources, forests, wildlife where human activities are completely banned is called National Park.

This PSEB 10th Class Science Notes Chapter 15 Our Environment will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 15 Our Environment

→ A biotic community survives in an environment entirely by materials and energy provided by its environment.

→ The environment is the sum total of all external conditions and influences that affect the life and development of an organism, i.e., the environment includes all the physical or abiotic and biological or biotic factors.

→ The ecosystem is defined as the interaction between the physical environment and the biotic community.

→ An ecosystem is a unit of the environment that can be identified and studied. The term ‘Ecosystem’ was coined by Sir Arthur Tansley (1935).

→ The various components of an ecosystem are interdependent.

→ An ecosystem can be natural or artificial, small or large, and temporary or stable. An ecosystem has a defined organization having two structural components i. e. biotic and abiotic.

→ The ecosystem may vary in sizes such as a small pond or a large forest or ocean.

→ Two major categories of ecosystems are terrestrial and aquatic ecosystems.

→ Its functional components include the volume and rate at which materials circulate and energy flow as well as the process of interaction between biotic and abiotic components.

→ The biotic components of any natural ecosystem comprise

• producers
• consumers (primary and secondary)
• decomposers.

→ Both materials and energy enter the living world through the producers.

→ There is always a unidirectional flow of energy in a food chain.

→ We have an impact on our environment.

→ Different materials are cycled in the environment in separate biogeochemical cycles.

→ In these cycles, essential nutrients change from one form to another.

→ Enzymes are always specific in their action.

→ Plastic can neither be decayed by micro-organisms nor by other dead organisms.

→ Those substances which can be decayed by micro-organisms are called biodegradable substances. And those which cannot be decayed are known as non-biodegradable substances.

→ The organisms like plants, animals, micro-organisms, human beings, and their physical surroundings interact with each other. They maintain a balance in nature.

→ Forest, ponds, and waterfalls are examples of natural ecosystems whereas gardens and fields are man-made artificial ecosystem.

→ All green plants and blue-green algae are called producers because they trap sunlight and prepare their own food.

→ All organisms directly or indirectly are dependent on producers for their survival.

→ Those organisms which are dependent on producers for food are called consumers.

→ Consumers mainly are of three types: herbivores, carnivores, or omnivores.

→ Various organisms are linked together for their food requirements and form a food chain.

→ Each step of a food chain forms a trophic level.

→ Autotrophs trap solar energy and transform it into chemical energy.

→ The green plants in the terrestrial ecosystems capture about 1% of the energy of sunlight and convert it into food energy.

→ Primary consumers change almost 10% of consumed food into organic matter.

→ A food chain basically consists of three or four levels.

→ The length and compressibility of food chains vary greatly.

→ Instead of a straight-line food chain, a branched relationship is developed. This branched-chain forms a web called a food web.

→ Many chemicals mix with soil and enter water bodies and become part of the food chain.

→ Non-biodegradable substances accumulate in our body which is called Bio-magnification.

→ The ozone layer protects us from ultraviolet rays coming from the sun towards the earth.

→ At higher levels of the atmosphere ozone (O₃) is a product of UV radiation acting on oxygen (O₂) molecules.

→ Chemicals like chlorofluorocarbons (CFCs) are responsible for the depletion of the ozone layer.

→ Improvements in our lifestyle have resulted in a greater amount of garbage.

→ Acid rain is the result of air pollution.

→ Global warming is due to the slow rise in the earth’s temperature due to an increase of CO₂ concentration in the atmosphere.

→ Global warming can be stopped by cutting down the use of fossil fuels.

→ Wastes are of two types i.e. biodegradable and non-biodegradable waste.

→ WHO (World Health Organisation) has defined solid waste as “a matter in the wrong place i.e., a non-liquid, no-gaseous substance no longer useful to the holder.”

→ Solid Waste is a by-product of human development and growth.

→ Approximately every resident of urban India generates about 500 g of solid waste.

Its generation is directly proportional to sources of income. Higher the income – greater is the consumption and bigger is the waste.

→ Solid waste is a heterogeneous mixture and may have different types of components.

→ Collection, treatment, and disposal of waste are important aspects requiring urgent consideration.

→ Modes of disposal of wastes are:

• Landfills: It is the method used in urban areas to bury the solid waste in low-lying areas to level the uneven ground.
• Recycling: It is the method of recovery and processing of biodegradable wastes or materials after they have been used, which enables them to be reused.
• Composting: In this method, domestic waste like fruit and vegetable waste, left-over food, leaves of potted plants, etc., can be converted into compost and used as manure.
• Incineration: It means ‘reduction to ashes’. The burning of a substance at a high temperature to form ash is called incineration. It is used to destroy household waste, chemical waste, and biological waste. Incineration is carried out in an incinerator.

→ Ecosystem: The interchange of energy and matter between biotic and abiotic components is called an ecosystem.

→ Biome: When ecosystems combine, a larger system is formed which is called a Biome.

→ Biosphere: When all the biomes of the world combine together resulting in a large unit it is termed as the biosphere. It is considered to be the largest biological system.

→ Hydrosphere: The part of Earth covered with water is called the hydrosphere.

→ Lithosphere: The outer crust of our planet Earth is called the lithosphere.

→ Atmosphere: The multi-layered gaseous envelope of air that covers the whole of our planet Earth like a blanket is termed as atmosphere.

→ Consumer: Those organisms which cannot produce their own food and consume already formed food are called consumers.

→ Nutrition: Nutrition is the process of providing or receiving nourishing substances with the help of the food chain.

→ Food chain: A chain formed by producers, consumers, and decomposers is called a food chain. It is a series of organisms feeding on one another at various biotic levels.

→ Food web: The network of overlapping food chains is called the food web.

→ Biogeochemical cycle: A constant interaction between the biotic and abiotic components of the biosphere makes it a dynamic but stable system. These interactions consist of a transfer of matter and energy between the different components of the biosphere.

→ Macronutrients: The nutrients which are required in large amounts by the body are called macronutrients, e.g. H, N, C, O, P.

→ Micronutrients: The nutrients which are required in small amounts by the body are called micronutrients, e.g. Mn, Zn, Cu, etc.

→ Water cycle: The whole process in which water evaporates and falls on the land as rain and water flow back into the sea via rivers is known as the water cycle.

→ Primary Consumers: Those organisms which eat plants or their products are known as herbivores or primary consumers.

→ Secondary consumers: Those organisms which eat the flesh of other animals are known as carnivores or secondary consumers.

→ Flora: The population of plants and trees in a region.

→ Fauna: The animal population of a region.

→ Community: Group of plants and animals living together e.g. plants and animals living in a pond.

→ Bio-magnification: Accumulation of non-biodegradable substances in large amounts in our body is called bio-magnification.

→ Biodegradable substances: Those substances which are broken down into simple substances by the decomposers in the life cycle are called biodegradable substances.

→ Non-biodegradable substances: Those substances which cannot be decayed by decomposers are called non-biodegradable substances.

→ Environment: Living organisms and their surroundings constitute the environment.

→ Ecology: It is a branch of science which deals with the relationship between living organisms and their environment on the basis of living and non-living components.

→ Components of Ecosystem: Physical, chemical, and living parts that form the ecosystem are called the components of the ecosystem.

→ Biogeochemical cycle: The constant interaction between biotic and abiotic components of the biosphere makes it a dynamic but stable system. These interactions consist of a transfer of matter and energy between different components of the biosphere.

→ Biological Magnification: The successive increase in the concentration of some toxic substances through different trophic levels of a food chain is called biological magnification.

→ Producer: Those plants and animals which convert solar energy into chemical energy and prepare their own food are called producers.

→ Decomposer: Those organisms which break down complex organic compounds from the surface of their bodies and convert them into simple inorganic substances with the help of enzymes are called decomposers.

→ Herbivores: Organisms that consume only plants and their products as food is called Herbivores.

→ Carnivores: Organisms which eat the flesh of other animals for survival are called carnivores.

→ Omnivores: Organisms that eat plants, animals, and their products are called omnivores.

→ Food Web: Branched food chain is called a food web.

→ Ozone layer: The layer of ozone in the stratosphere is called as ozone layer.

→ Garbage: The waste accumulated by common domestic and agricultural activities is known as garbage.

This PSEB 10th Class Science Notes Chapter 14 Sources of Energy will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 14 Sources of Energy

→ No activity is possible without energy.

→ Renewable sources of energy are sun, water, and wind, etc.

→ Substances having low ignition temperatures are called inflammable substances.

→ Substances burn at a moderate rate during slow combustion. Substances burn in a very short span of time during rapid combustion.

→ During spontaneous combustion substances suddenly catch fire when their temperature is raised above ignition temperature.

→ Gobar gas is produced by fermentation of cow-dung by anaerobic bacteria.

→ Gobar gas or biogas is a fuel of high calorific value.

→ Solar energy is the combination of visible infrared radiations and invisible (ultra-violet) energy radiated out by the sun.

→ Solar cookers, solar heaters, solar furnaces, and solar cells are devices using solar energy.

→ Solar cells convert solar energy directly into electric energy. Solar cells are used to supply electric energy to watches, calculators, and satellites.

→ Excessive use of any source of energy disturbs the environment. We should try to use non-polluting (clean), economical and efficient sources of energy.

→ Non-polluting sources of energy like solar and wind energy need to be promoted.

→ It is neat and clean energy which is available free of cost.

→ Energy: The capacity of doing work is called energy.

→ Kinetic Energy: It is the energy possessed by a body due to motion, e.g., moving air, running water, etc.

→ Solar Energy: The energy obtained from the sun.

→ Wind Energy: The kinetic energy contained in a large mass of air in motion is called wind energy.

→ Solar Cooker: It is a device that uses solar energy for cooking food.

→ Solar Cell: A device that converts solar energy into electric energy.

→ Ocean Thermal Energy (O.T.E.): There is always the same temperature difference- between water at the surface of the ocean and water at the depth. This difference can be even 20° C. The energy available in this form is called ocean thermal energy.

→ Salinity Ingredients: The variation of concentration of salt is called salinity ingredient.

→ Fuel: Those substances which burn to produce heat energy are called fuels.

→ Biomass: The material present in the bodies of plants and animals is known as biomass.

→ Biogas: It is a mixture of methane (CH₄), Carbon dioxide (CO₂), and Hydrogen Sulphide (H₂S) gas. It is produced by anaerobic fermentation of plants and animals waste (Gobar) and human wastes (feaces) in the presence of water.

→ Destructive Distillation: The process of heating in the absence of air to a high temperature is called destructive distillation. From the destructive distillation of coal-coaltar, coke and coal gas are obtained.

→ Fossil Fuel: Fossil fuel is formed by dead remains of plants and animals under the surface of the earth due to changes in temperature and pressure. Coal, petroleum, and natural gas are fossil fuels.

→ Liquefied Petroleum Gas (L.P.G.): Liquefied Petroleum Gas is a domestic fuel. It is a mixture of ethane, butane, and isobutane gases.

→ Synthetic Petroleum: It is formed by the reaction of coal with hydrogen at high temperatures and pressure.

→ Ignition Temperature: That particular temperature at which a substance starts burning is called ignition temperature.

→ Calorific Value of Fuel: The amount of heat produced by the complete combustion of 1 g mass of a fuel is called the calorific value of the fuel.

→ Slurry: The mixture of gobar (cow dung) and water obtained as a residue in the biogas plant is called slurry.

→ Propellant: Rocket fuel is called propellant. It is a mixture of some concentrated fuel and oxidizing substances.

→ Tidal Energy: That energy that is produced due to the rise and fall of the water level is called tidal energy.

→ Wave Energy: That energy that is produced due to the kinetic energy of waves near the seashore is called wave energy.

→ Geothermal Energy: Due to changes in the interior of the earth, energy produced from the conversion of underground water into steam is called geothermal energy.

→ Nuclear Energy: The energy produced due to nuclear fission reactions of atoms of heavy metals is called nuclear energy.

→ Nuclear Fission: The process of splitting of an atom of the heavy nuclear element by the bombardment of neutrons into light nuclei with the evolution of energy is called nuclear fission.

→ Nuclear Fusion: The process of combining light nuclei to form a heavy nucleus with the release of energy is called nuclear fusion.

→ Greenhouse Effect: The increase of temperature of the atmosphere due to the absorption of ultraviolet rays coming from the sun by carbon dioxide (CO₂) present in the air is called the greenhouse effect.

This PSEB 10th Class Science Notes Chapter 13 Magnetic Effects of Electric Current will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 13 Magnetic Effects of Electric Current

→ A current-carrying conductor behaves like a magnet. Magnet and electricity are related to each other.

→ Hans Christian Oersted did remarkable work to make us understand electromagnetism.

→ That end of freely suspended magnet which points towards north direction is called North Seeking or the North Pole and the other end which points towards south direction is called South Seeking or the South Pole.

→ Like poles repel each other while unlike poles attract each other.

→ The field or area around a magnet in which its effect or force can be experienced is called the magnetic field of the magnet.

→ The direction of magnetic lines of force inside the magnet is from the south pole to the north pole while outside the magnet it is from the north pole to the south pole. Therefore, magnetic lines are closed curves.

→ Two magnetic lines of force never intersect each other.

→ On passing a current through a metallic conductor, the magnetic field is produced around it.

→ The magnetic field produced all around it is inversely proportional to its distance.

→ The magnetic field at a point inside the magnetic field produced due to the current flowing through a conductor is proportional to the current flowing through the conductor.

→ A coil consisting of a cylindrical-shaped coil having closely packed turns of insulated copper wire is called a solenoid.

→ Inside a solenoid, magnetic lines of force are just like parallel straight lines. The magnetic field is the same at all points inside the solenoid.

→ The force acting in a conductor is in the direction of current and perpendicular to the direction of the magnetic field. This is called Fleming’s left-hand rule.

→ Electric motor, electric generator, loudspeaker, microphone, and electric meter are related with current-carrying conductor and magnetic field.

→ Production of the magnetic fields is necessary for our heart and brain.

→ MRI is important in medical treatment.

→ The electric motor is a device in which electrical energy is transformed into mechanical energy.

→ Electric motors find their use in electric fans, refrigerators, electric mixers, washing machines, computers, MP3 players, etc.

→ In electric motors, a rectangular coil of insulated wire is placed in between two poles.

→ That device that alternately changes the flow of current is called an AC motor.

→ Soft iron core and coil together form an armature. This increases the power of the motor.

→ Faraday discovered how the moving magnet can be used in producing current.

→ A galvanometer is an instrument that is used to detect the presence of current in a circuit.

→ That process by which the change in the magnetic field of a conductor produces a current in another conductor is called electromagnetic induction.

→ When the direction of motion of a coil is perpendicular to the direction of the magnetic field, then the induced electric current in the coil becomes maximum.

→ In electric generators, mechanical energy is used to rotate a conductor placed in a magnetic field as a result of which current is produced.

→ The device used to produce electricity is called an A.C. generator.

→ Electromagnet: A soft iron piece placed inside an insulated conducting coil becomes an electromagnet on passing current.

→ Magnetic Field: The field around a magnet in which its effect can be felt.

→ Solenoid: A coil made by winding a conducting wire having a large number of closed turns.

→ Iron Core: The soft iron rod placed inside the solenoid is called the iron core.

→ Snow Rule: When a wire placed above a magnetic needle carries current from the south direction to the north direction then the north pole (N-pole) of the magnetic needle gets deflected westward.

→ Electromagnetic Induction: Due to change in the magnetic field the current produced in the neighboring coil is called electromagnetic induction.

→ Electric Energy: The capacity for doing work by an electric current is known as electric energy.

→ Electric Power: The rate at which electric energy is consumed in a conductor is called electric power.

→ Electric Generator: The instrument which produces electric current is called an electric generator.

→ Alternating Current (A.C): That current which continuously changes direction alternately is called alternating current.

→ Direct Current (D.C.): That current which has the same direction always is called direct current (D.C.)

→ Short Circuit: When the live wire comes in direct contact with the neutral wire due to damaged wiring or uncovered wire, the resistance of the circuit becomes zero, and the current flowing through the circuit increases suddenly. This is called short-circuiting.

→ Fuse (Safety Fuse): A wire of low melting point connected in an electric circuit is called a fuse.

→ Electric Meter: A device that is connected to an electric circuit to measure electric energy being used is called an electric meter.

→ Electric Shock: When any part of the human body touches any point of the unsheathed (without insulation) circuit having high potential, shock is experienced which is known as electric shock.

→ Overloading: If the current through a circuit is more than the maximum prescribed limit then the wires become hot and may catch fire. It is called overloading.

→ Right Hand Thumb Rule: If we imagine that current is passing through a conductor held in your right hand such that the thumb points in the direction of current then the curling fingers would represent the direction of the magnetic field.

→ Flemming’s Left-Hand Rule: Stretch your left hand in such a way that the first central fingers are mutually perpendicular to each other, then if the first finger points in the direction of the magnetic field, the central finger in the direction of current then the thumb points in the direction of motion of the conductor.

→ Earthing: The joining of metallic frame of the electric appliance of high power with the earth wire of domestic circuit is called earthing.

This PSEB 10th Class Science Notes Chapter 12 Electricity will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 12 Electricity

→ Electric current is the rate of flow of charge Q through the conductor or it is the charge Q flowing per unit time i.e., I = \(\frac{Q}{t}\)

→ Charge always flows from a body at a higher potential to a body at a lower potential.

→ Electrostatic potential determines the direction of flow of charge from one body to the other when they are brought in contact.

→ Electrostatic potential at a point is defined as the amount of work done is bringing a unit positive test charge from infinity to that point.

→ Conductors have a large number of free electrons whereas insulators have very few free electrons. The motion of free electrons constitutes the electric current.

→ An electric circuit is a closed path through which electrons flow readily.

→ As per convention, the direction of current is taken as opposite to the direction of the flow of electrons.

→ Electric Current: The rate of flow of charge through a conductor is called electric current.
I = \(\frac{Q}{t}\)

→ Ohm: The resistance of a conductor is said to be 1 ohm if a potential difference of 1 volt is maintained between its ends and it allows 1 ampere of current to flow through it.

→ Voltmeter: It is a device used to measure the potential differences.

→ Conductor: Those substances which allow the current to flow through them are called conductors or good conductors.

→ Insulators: Those substances which do not allow the current to flow through them are called insulators.

→ Ammeter: It is an instrument used to measure electric current.

→ Rheostat: It is a device that is used to increase or decrease the current flowing through the electric circuit.

→ One Volt: If 1 coulomb of charge is allowed to pass through a conductor and in doing so 1 joule of work is done then the potential difference across its ends is 1 volt.

→ Ohm’s Law: The ratio of potential difference across the ends of a conductor and the current flowing through it is always constant, provided the physical state of the conductor such as temperature and pressure remains unchanged.
i.e. V ∝ I or \(\frac{V}{I}\) = R

→ Electrical Energy: The capacity of doing work by an electric current is called electrical energy.

→ Electric Power: The rate of consumption of electric energy in a conductor is called electric power.

→ Watt: Watt is an S.I. unit of electric energy in which 1 joule of work is done in 1 sec. Kilowatt. It is the power of an agent which can do 1000 joule of work in 1 second.

→ Kilowatt Hour: It is that electric energy which is consumed in an electric circuit in 1 hour.

→ Coulombs’ Law: Electric force between two charged particles is directly proportional to the product of the two charges and inversely proportional to the square of the distance between them.
F = K\(\frac{q_{1} q_{2}}{r^{2}}\)

→ Joule’s Law of Heating Effect. If T is the electric current that flows through a resistor ‘R’ and as a result of which heat produced is ‘H’. Then heat produced is directly proportional to the square of the current and time ‘t’
H = I² Rt

This PSEB 10th Class Science Notes Chapter 11 The Human Eye and The Colourful World will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 11 The Human Eye and The Colourful World

→ The eye is the most useful natural optical instrument.

→ Distance between near and far points is called accommodation.

→ The least distance of distinct vision for a normal eye is 25 cm.

→ The retina is the most sensitive part of the eye.

→ Rods present on the retina are sensitive to the intensity of light and cones are sensitive to colours of light.

→ The most sensitive part of the retina where the image of the object is formed is called the yellow spot.

→ The focal length of the eye lens can be varied with the help of ciliary muscles.

→ The defects of the eye are myopia, hypermetropia, presbyopia, astigmatism, and colour blindness.

→ Colour blindness cannot be cured while myopia can be corrected by using a diverging (say a concave) lens of suitable focal length.

→ Hypermetropia can be corrected by using a converging (say a convex) lens of suitable focal length. For correcting presbyopia, bifocal lenses are required. Astigmatism is corrected by using a cylindrical lens.

→ Eyes can be donated after death. Even a person using spectacles, contact lens or who have been operated on for cataract or suffering from hypertension can also donate eyes.

→ The cornea of dead persons’ eyes is removed within 6 hours of death and transplanted in blind persons’ eyes.

→ Eye Lens: It is a convex lens made of a fibrous jelly-like substance on the retina of which the real and inverted image of the object is formed.

→ Cornea: It is a transparent membranous bulged out coating in the front part of the eyeball through which light enters the eye, is called the cornea.

→ Iris: The structure just behind the cornea which controls the size of the pupil is called the iris.

→ Myopia: It is the defect of the eye in which the near objects are clearly visible while distant objects are not distinctly visible.

→ Hypermetropia: The defect of the eye in which the distant objects are clearly visible whereas the near objects are not.

→ Retina: It is a delicate membrane having a large number of light-sensitive cells that become active on being illuminated produce electric signals carried to the brain.

→ Near Point: The shortest distance at which if an object is placed is seen clearly without any strain, is called the near point of the eye.

→ Far Point: The farthest point at which an object is placed is seen very clearly.

→ Cataract: The formation of a milky translucent layer on the crystalline lens is called a cataract which results in less visibility and ultimately complete loss of eyesight.

→ Least Distance of Distinct Vision: The minimum distance at which if the object placed can be seen very clearly is called the least distance of distinct vision.

→ Colour Blindness: That defect of the eye in which a person can see clearly but can not distinguish colours is called colour blindness.

→ Persistence of Vision: The sensitiveness of the retina which retains the existence of image for \(\frac{1}{216}\)th of a second even after when it is actually removed.

→ Presbyopia: With aging, the power of accommodation of eyes decreases, and the person cannot read. This defect is due to the weakening of the ciliary muscles.

→ Bifocal Lens: Defect of the eye in which a person suffers both from myopia and hypermetropia. Such a person needs a bifocal lens consisting convex lens (lower part) to see near objects and a concave lens (upper part) to see far-off objects.

→ Prism: It is a piece of a transparent refracting medium having two triangular and three rectangular surfaces. These surfaces are inclined to each other.

→ The angle of Prism: The angle between two surfaces of the prism is called the angle of prism.

→ Tyndal Effect: If a strong beam of light is passed through a colloidal solution, the path of the beam becomes visible when seen with a microscope placed at a right angle. This effect is called the Tyndal effect.

This PSEB 10th Class Science Notes Chapter 10 Light Reflection and Refraction will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 10 Light Reflection and Refraction

→ Light is an external physical agent which produces in us the sensation of sight.

→ When light travelling in one medium falls on the surface of another medium, the following three effects are observed:

• A part of the incident light is turned back (or reflected) into the first medium.
• Another part travels through the second medium along a changed path (i.e the fight is refracted).
• The remaining part is absorbed by the second medium.

→ Objects are always placed in front of the mirror to their left, so u (object distance) is always negative.

→ The focal length of the convex mirror is taken as positive (+) and that of the concave mirror as negative (-).

→ Magnification of a concave mirror forming real image is m = \(\frac{v}{u}\) and that of convex mirror and also a concave mirror forming virtual image is m = \(\frac{-v}{u}\).

→ All distances measured in the direction of the incident light are taken as positive and distances measured in a direction opposite to the incident ray are taken as negative.

→ The phenomenon of bending of a light ray when it travels from one medium to another medium of different optical densities is called the refraction of light.

→ When a ray of light travels from an optically rarer to an optically denser medium, it bends towards normal.

→ When a ray of light travels from an optically denser to an optically rarer medium, it bends away from normal.

→ The higher the refractive index the more is the denser medium.

→ The ratio of the sine of the angle of incidence (Sin i) to the sine of the angle of refraction (Sin r) is constant, called the refractive index of the medium.

→ The Refractive index of a medium is the ratio of the velocity of light in a vacuum to the velocity of light in a medium.

→ The lens is a portion of the transparent and refracting medium.

→ The relation between the object distance (u), the image distance (v) and the focal length (f) of a lens is called lens formula i.e. \(\frac{1}{f}=\frac{1}{v}-\frac{1}{u}\)

→ The power of a lens is the reciprocal of its focal length. Its unit is dioptre.

→ Mirror: Any smooth and polished surface is called a mirror.

→ Reflection of Light: When light falls on a mirror or a polished surface then without any change in the medium it returns into the same medium along a particular direction. This phenomenon of change of path of light is called reflection.

→ Incident Ray: A ray of light coming from a source of light falling on any surface is called an incident ray.

→ Reflected Ray: After reflection, a ray of light coming back from point of incidence into the same medium is called a reflected ray.

→ Incident Point: The point on the reflecting surface where incident ray strikes is called incident point.

→ Normal: The perpendicular drawn at the point of incidence is called normal.

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

→ The angle of Reflection: The angle between the reflected ray and the normal is called the angle of reflection.

→ Ray of Light: The straight path of light is called a ray of light.

→ Spherical Mirror: If the mirror is a part of some hollow sphere whose one surface is polished and the other surface is reflecting then such mirror is called a spherical mirror.

→ Concave Mirror: A spherical mirror whose reflecting surface is towards the centre of a hollow sphere of which the mirror is a part, is called a concave mirror.

→ Convex Mirror: A spherical mirror whose reflecting surface is away from the centre of a sphere of which the mirror is a part, is called a convex mirror.

→ Centre of Curvature: Centre of curvature of a spherical mirror is the centre of a sphere of which the mirror is a part.

→ Pole: The midpoint of a spherical mirror is called the pole of the mirror.

→ Principal Axis: An imaginary line joining the pole and centre of curvature of a spherical mirror is called the principal axis.

→ The radius of Curvature: It is the radius of a sphere of which the spherical mirror is a part.

→ Aperture: That part of the mirror from where actually reflection takes place is called the aperture of the mirror.

→ Principal Focus: It is the point on the principal axis where the rays of light coming parallel to the principal axis after reflection actually meet or appear to diverge is called the principal focus of the mirror.

→ Focal Length: The distance between pole and principal focus of spherical mirror is called the focal length of the mirror. It is usually denoted by f.

→ Magnification: The magnification of a spherical mirror is the ratio of the length (size) of the image to the length (size) of the object. It is denoted by ‘m’.

→ Refraction of Light: The change of path of light when it goes from one medium to another medium is called refraction of light.

→ Transparent Medium: Mediums like air, water, and glass through which light can pass easily are called transparent mediums.

→ Lens: A portion of transparent and refracting medium bounded by two surfaces is called the lens.

→ Power of Lens: The capacity of a lens to converge or diverge light rays is called the power of the lens. It is denoted by ‘P’.

→ Centres of Curvature of Lens: The centres of spheres of which the spherical surfaces of the lens are part, are called centres of curvature of the lens.

→ Principal Axis of Lens: The line passing through the centres of curvature of the lens, is called the principal axis of the lens.

→ Optical Centre: A point of the lens through which rays of light go undefeated, is called an optical centre.

→ Principal Focus of Lens: The point on the principal axis of the lens, where rays coming parallel to the principal axis after refraction either actually converge or appear to diverge, is called the principal focus of the lens.

This PSEB 10th Class Science Notes Chapter 9 Heredity and Evolution will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 9 Heredity and Evolution

→ Heredity: It is the transmission of genetic characters from parents to the offspring i.e., from one generation to the next.

→ Variation: The differences among the individuals of a species and also in the offsprings of the same parents are referred as a variation.

→ Every organism produce offsprings either through asexual or sexual reproduction. The individuals produced through these reproductive processes are similar but subtly different.

→ In asexual reproduction, although all the offsprings resemble each other and also to their single parent, yet very minor differences (variations) arise in them.

→ For example, if we observe a field of sugarcane we find very few variations among the individual plants.

→ The reproductive processes give rise to new individuals that are similar, but subtly different.

→ The number of successful variations is maximized by the process of sexual reproduction.

→ Inheritance from the previous generation provides both a common basic body design and subtle changes in it, for the next generation.

→ The second generation will have differences that they inherit from the first generation, as well as newly created differences.

→ Some amount of variation is produced even during asexual reproduction.

→ The selection of variants by environmental factors forms the basis for evolutionary processes.

→ A child bears all the basic features of a human being.

→ Both the father and the mother contribute practically equal amounts of genetic material to the child.

→ Mendel was the first one to keep count of individuals exhibiting a particular trait in each generation.

→ Mendel used a number of contrasting visible characters of a garden pea. Cellular DNA is the information source for making proteins in the cell.

→ A section of DNA that provides information for one protein is called the gene for that protein.

→ Plant height can also depend on the amount of a particular plant hormone. Genes control characteristics or traits.

→ Each cell will have two copies of each chromosome, one each from the male and female parents.

→ Every germ cell will take one chromosome from each pair and these may be of either maternal or paternal origin.

→ In some animals, the temperature at which fertilized eggs are kept determines whether the animals developing in the eggs will be male or female.

→ In other animals, such as snails, individuals can change sex, indicating that sex is not genetically determined.

→ Human has 23 pairs of chromosomes.

→ Women are XX, while men are XY.

→ The frequency of inherited traits changes over generations.

→ The germ cells of sexually reproducing populations are made in specialized reproductive tissue.

→ Change in non-reproductive tissues cannot be passed on to the DNA of the germ cells..

→ An individual cannot pass on to its progeny the experiences of its lifetime.

→ Charles Darwin formulated in his hypothesis that evolution took place due to natural selection.

→ We often associate Darwin solely with the theory of evolution.

→ J.B.S. Haldane, a British scientist (who became a citizen of India later), suggested in 1929 that life must have developed from the simple inorganic molecules which were present on earth soon after it was formed.

→ Some basic characteristics will be shared by most organisms.

→ The cell is the basic unit of life in all organisms.

→ Bacterial cells do not have nuclei while the cells of most other organisms do.

→ Among multicellular organisms, whether they can undertake photosynthesis or not, is an important level of classification.

→ The skeleton is inside the body or around the body is another fundamental design difference.

→ The more characteristics two species will have in common, the more closely they are related.

→ The more closely they are related, the more recently they will have had a common ancestor.

→ Non-living material must have given rise to life.

→ The characteristics in different organisms would be similar because they are inherited from a common ancestor.

→ Mammals have four limbs, as do birds, reptiles, and amphibians.

→ The wings of birds and bats are more closely related to each other.

→ The preserved traces of living organisms are called fossils.

→ If we dig into the earth and start finding fossils, it is reasonable to suppose that the fossils we find closer to the surface are more recent than the fossils we find in deeper layers.

→ The dating of fossils is done by detecting the ratios of different isotopes of the same element in the fossil material.

→ The complex organs 4vill be created bit-by-bit over generations.

→ Like the wing, the eye seems to be a very popular adaptation.

→ The structure of the eye in different organisms is different. It shows that they have separate evolutionary origins.

→ A flatworm named Planaria has very simple ‘eyes’ that are really just eye spots that detect light.

→ A change that is useful for one property to start with, can become useful later for quite a different function.

→ Feathers, for example, can start out as providing insulation in cold weather but later, they might become useful for flight.

→ The birds are very closely related to reptiles.

→ Humans have started cultivating wild cabbage as a food plant for over more than two thousand years and generated different vegetables from it by selection.

→ Changes in the DNA during cell division would lead to changes in the proteins that are made from new DNA.

→ The organisms which are more distantly related will accumulate a greater number of differences in their DNA.

→ It is not true that human beings have evolved from chimpanzees. The two resultant species have probably evolved in their own separate ways to give rise to the current forms.

→ Evolution is simply the generation of diversity and the shaping of diversity by environmental selection.

→ The tools for tracing evolutionary relationships are excavating, time-dating, and studying fossils, as well as

→ DNA sequences determination has been used for studying human evolution.

→ All humans are a single species. We all come from Africa.

→ The earliest members of the human species, Homo sapiens, can be traced in Africa.

→ The origin of man, like other species on the earth, is an event of biological evolution.

→ Genetics: The branch of biology which deals with the study of heredity and variation is called genetics.

→ Heredity: The transmission of characters from generation to generation is called heredity.

→ Gene: The basic unit of heredity which transmits the traits into the next generation.

→ Sex chromosome: The pair of chromosomes which decide the sex of male and female.

→ Homologous chromosome: The pair of chromosomes each from mother and father together is called a homologous chromosome.

→ Autosomes: The chromosomes other than sex chromosomes are autosomes.

→ Evolution: The slow and continuous process of changing organisms from simple to complex form is called evolution. In simple words descend with modification.

→ Homologous organs: The organs have the same origin and basic structure but are adapted to perform various functions.

→ Analogous organs: The organs have a different origin and basic structures but perform the same function.

→ Transgenic organism: The organism produced by the introduction of foreign DNA or genes.

→ Fossils: The remains of dead animals in earth strata are called fossils.

→ Haploid: The single set of chromosomes obtained from one parent.

→ Nucleotide: A molecule made up of nitrogen base, sugar, and phosphate.

→ Chromatid: When the chromosomes divide into two each part is called a chromatid.

→ Vestigial organs: Organs in our body having no functional importance are called vestigial organs.

→ Genetic drift: The effect on the genetic continuation in a population due to the death of organisms or immigration is called genetic drift.

→ Variations are differences between young one of the same parent: They differ from their parents.

→ Variations arise due to inaccuracies in DNA replication in asexually reproducing organisms.

→ Offsprings: Young ones produced as reproduction are ailed offsprings.

→ Genotype: The internal genetic constitution of an organism is termed genotype. The environment has no effect on it.

→ Phenotype: It refers to externally visible characters of an organism. It is the net result of interactions between genotype and environment. Individuals of the same genotype breed alike are termed phenotype.

→ Recessive traits: An allele (gene) that is not expressed phenotypically when present in heterozygous conditions.

→ Speciation: The origin of species is termed speciation.

→ Acquired characters: The characters acquired during a lifetime are ailed acquired characters.

→ Life: Life is the power that an organism possesses to maintain and reproduce itself.

→ Natural selection: According to Darwin the individual with special traits survive and multiply while others perish is called natural selection.