Srinivas

Students can go through AP State Board 8th Class Social Studies Notes Chapter 15 Law and Justice: A Case Study to understand and remember the concept easily.

AP State Board Syllabus 8th Class Social Studies Notes Chapter 15 Law and Justice: A Case Study

→ If you have to make a complaint to the police, it is necessary to file an FIR at the police station.

→ A copy of the FIR should be given free of charge to the person making the report.

→ One important function of the police is to investigate any complaint about the crime.

→ It is not the job of the police to punish the accused.

→ Civil cases are related to people’s rights over land, property, income and people’s relationships with one another.

→ The police take charge of the criminal case because it is a violation of law made by the government.

→ Bail is a right of the accused.

→ A criminal offence is registered as a public wrong.

→ The judge is like an umpire in a game and conducts the trial impartially and in an open court.

→ One of the central features of the Constitution is to separate the powers of Executive, Judiciary and Legislative.

→ Each state has a High Court which is the highest court of that state.

→ Supreme Court is located in New Delhi.

→ Accused: The person who has done something wrong.

→ FIR: First Information Report gathered by the police.

→ Offence: A breach of law or rule; an illegal act.

→ Investigation: A formal inquiry or systematic study.

→ Arrest: To seize a person by legal authority or warrant.

→ Summons: An order to appear before a judge or magistrate.

→ Witness: One who furnishes evidence.

→ Fair Trial: A trial by a neutral and fair court.

→ Judgement: The legal document stating the reasons for a judicial decision.

→ Appeal: To make a serious or urgent request to the public.

→ Breach of contract: Failure to do something that is required in a contract.

→ Client: A person receiving social or medical services.

→ Public Prosecutor: A law officer who conducts criminal proceedings on behalf of the government or in the public interest.

→ Bail: The temporary release of an accused person awaiting trial.

→ ‘Magistrate: A civil officer or judge who administers the law, especially who conducts a court that deals with minor offences.

Students can go through AP State Board 9th Class Social Studies Notes Chapter 6 Agriculture in India to understand and remember the concept easily.

AP State Board Syllabus 9th Class Social Studies Notes Chapter 6 Agriculture in India

→ Agriculture is an age-old economic activity in our country. Farming varies from subsistence to commercial type.

→ Subsistence farming: This type of farming is alone in two forms. They are Simple Subsistence Farming and Intensive Subsistence Farming.

→ Commercial farming: The main characteristic of this type of farming is the use of higher doses of modern inputs, chemical fertilizers, insecticides, and pesticides in order to obtain higher productivity. The plantation is also a type of commercial farming.

→ Agriculture crops depend on seasons and natural resources such as soil, water, and sunshine for cultivation. India has three cropping seasons.

1. Rabi
2. Kharif
3. Zaid

→ Major Crops: A variety of food and non-food crops are grown in different parts of the country.

Major crops grown in India are:

• Rice: It is a Kharif crop. High temperatures, heavy rainfall, and high humidity are essential for rice. Grown in the plains of north and northeastern plains of India.
• Wheat: It is a winter crop. Grown in the northern part of our country.
• Maize: It is used both as food and fodder. It is grown in old alluvial soil Major Maize producing states are Karnataka, Uttar Pradesh, Bihar, Telangana, Andhra Pradesh, and Madhya Pradesh.

→ Millets, Pulses, Sugarcane, Oilseeds, Tea are some other important crops.

→ Horticulture Crops: India is the largest producer of fruits and vegetables in the world

→ Non-Food Crops: Rubber, fiber crops such as cotton, jute, silk are important non-food crops.

→ Environmental Effects of New-Agricultural Technologies: The Green Revolution has brought in several environmental imbalances: In Punjab, Haryana, and parts of Uttar Pradesh, most farmers have shifted to the cultivation of HYVs of rice and wheat, which require plenty of water.

→ The food security of a nation depends on agriculture. A variety of raw materials required for industries are cultivated on farms. Agriculture is also a major source of livelihood for millions.

→ Two kinds of people are engaged in farming – agricultural laborers and cultivators.

→ A variety of crops are cultivated by farmers in India. They are food grains and non-food grains.

→ There are two challenges for the country

1. to grow food in sufficient quantity and
2. to ensure that people are not undernourished even when we have food available.

→ Agriculture crops depend on seasons and natural resources such as soil and water and sunshine for cultivation. Temperature and humidity conditions are important

→ The newly formed Indian Government also made (initiated) other important policy changes.
(a) The First Phase: Between 1950-65, big dams for irrigation and electricity generation like Bhakra-Nangal, Damodar Valley, Hirakund, Nagarjuna Sagar, etc. were constructed.

(b) The Second Phase – Green Revolution and its Spread: The government introduced a new kind of seeds to the Indian soil It was also accompanied by the use of chemical fertilizers, machinery such as tractors, and others besides irrigation facilities. High Yielding Varieties of seeds and fertilizers were the key elements of new agricultural technologies.

→ Effects of Green Revolution: The spread ofHYVs to large parts of the country and to newer crops have led to a significant increase in crop production in the country. As a result of the import of food- grains from other countries were reduced. Today farmer is able to produce nearly 800 kilograms of foodgrains per acre of cultivable land

→ The Green Revolution has brought in several environmental imbalances.

(c) The Third Phase – Post reform agriculture: Foreign trade in food products was not allowed The Government started offering minimum support prices. Thus the Indian farmer produced for markets within the country.

→ In recent years, however, the support of the government has not been so strong. For example, the government has started only a very few new irrigation projects. So a large section of farmers are compelled to depend on rainfall

→ Chemical fertilizer: Fertilizers that are prepared by using petro-chemicals are called chemical fertilizers. They are proved to be harmful to agriculture.

→ Green Revolution: It is a specific program introduced to increase the productivity of agriculture by using a high-yielding variety of seeds.

→ Organic Material: The material obtained from degrading all the biological waste in the compost pit can be termed as organic material.

→ Dryland Agriculture: The agriculture carried on the lands which cannot easily be irrigated is known as dryland agriculture.

→ Modern Farming Practices: The use of High Yielding Varieties of seeds, fertilizers, and use of machinery, etc., are modern farming practices.

→ Foreign Trade Policy: Policy of government regarding imports and exports.

→ Bio-chemical: Bio-chemical fertilizers are prepared by using biological materials. often they are used to enrich the soil.

→ Tropical climate: The hot climate which can be experienced within the tropics.

→ Environmental problems: Problems related to our environment are called environmental problems.

→ Environmental imbalances: Any disturbance created to our natural surroundings in which we live or exist. e.g.: Reduction in groundwater levels etc.

→ High Yielding Varieties: High Yielding Varieties of seeds and fertilizers were the key elements of new agriculture technologies. The HYV5 seeds grew well when fertilizers and water were used; they had larger amounts of grain and shorter stalks and a short period of maturity in most cases. The short period of maturity also enables double cropping-farmers can to use their lands more than once a year.

→ This policy was initially implemented in Punjab, Haryana, Western Uttar Pradesh, and in some districts of Andhra Pradesh and Tamilnadu. The HYV seeds required a lot of water and these areas were already irrigated. The new variety of wheat was grown in Punjab, Haryana, and Western Uttar Pradesh, while the rice was grown in Andhra Pradesh and Tamilnadu.

→ Organic Farming – The experience of a farmer in Odisha: In order to overcome the ill effects of the Green Revolution, farmers in India have begun to adopt different farming practices. Let us look at an example. Aged 80, Natwarbhai is a resident of Narishu village, near Niali in Cuttack district, Odisha. A retired school teacher, he has been practicing organic farming for the last decade or so, and swears by its potential to feed India’s population. He says some of the varieties he grows yield over 20 quintals per acre, higher than the so-called ‘high yielding varieties that farmers around him get after using chemical fertilizers and pesticides. And he spends much less since his main inputs are gobar, natural pesticides when occasionally needed, and family labor.

→ Natwarbhai was earlier a ‘modern’ farmer. One day, while watching a laborer spray Carbofuran (a highly toxic pesticide), he was horrified to see him stagger and collapse. Rushed for treatment, the worker survived, but not Natwarbhai’s faith in the new agriculture. Especially after the laborer told him: “I could not breathe, my head was reeling”; and especially after, having buried the remaining stock of Carbofuran in a pit in his fields, Natwarbhai “saw dead snails, snakes, and frogs floating in the water that had accumulated there. “I immediately wondered what would be happening to the earthworms and micro-organisms that I knew kept the soil alive.” Natwarbhai switched to organic inputs, but with the high yielding varieties that them all, noting down their names, characteristics, and productivity.

→ What is fertile soil?
To be fertile, the soil has to provide the roots of plants with the right amounts of water, minerals, and air. To do this, it must have the correct texture and the correct composition. Soil is composed of mineral particles (which come from the breakdown of rocks) as well as organic components (which are or have come from living organisms). To be available to roots, the minerals must be dissolved in the water.

→ Why Government buys and stores some grain?
A lot of grain comes into the market at harvest time. One problem farmers faced was the low price of grain during this time. This means farmers were not able to sell grain at a high enough price to be able to repay their loans and continue using the new farming methods. They need to be protected from traders who might try to purchase the grains at low prices. Therefore, the government decided to set a Minimum Support Price (MSP). A Minimum Support Price is a price at which the farmers can sell their grain, if they want, to the government. The government sets the MSP so as to cover the cost of cultivation and allow a little bit of profit to the farmer. Because of the MSP, farmers are not forced to sell their grains at cheaper prices to the traders.

→ The Food Corporation of India (FCI) was formed by the government to purchase food grains from the farmers and store them. It keeps stockpiles and supplies grain to ration shops and other government schemes (e.g. for midday meals in schools).

Students can go through AP State Board 8th Class Social Studies Notes Chapter 14 Parliament and Central Government to understand and remember the concept easily.

AP State Board Syllabus 8th Class Social Studies Notes Chapter 14 Parliament and Central Government

→ The Constitution provides a parliamentary form of government.

→ Lok Sabha TV telecasts daily the discussions taking place in the Parliament.

→ In 1986, the Parliament adopted a National Policy on Education.

→ There are two houses of Parliament – Lok Sabha and Rajya Sabha.

→ Any ordinary law needs to be passed by both houses. Lok Sabha exercises more powers in money matters.

→ Normally, elections to the Lok Sabha are held every five years.

→ The first general elections were held in 1951-52.

→ An Election Commission was set up to conduct the elections in a free and fair manner.

→ In an ideal situation, every voter is expected to know about the different candidates, their policies and decide whose policies they would prefer and who they think can represent their interests best in the Parliament and then vote.

→ The Election Commission in recent times has taken very strict measures to control illegal practices.

→ The MLAs of all the states and the members of both houses of the Parliament elect the President.

→ The Prime Minister and the Council of Ministers are chosen from among the members of Parliament.

→ All decisions of the government of India are taken in the name of the President.

→ Legislature: The house which is constituted by the elected members of the state in our election. (By the voters)

→ Lok Sabha: The house which is constituted by the elected members of the nation. This is also known as Lower House.

→ Rajya Sabha: Some wise people are elected to this and some are nominated. This is also known as Upper House.

→ Election Commission: An independent statutory body in India

→ Council of Ministers: The Prime Minister appoints some members of Parliament to this council. This is known as the Council of Ministers.

→ Central list: Subjects on which laws can be made only by the Parliament.

→ State list: Subjects on which laws can be made only by State Legislature Assemblies.

→ Concurrent List: Subjects on which laws can be made by both Parliament and State Legislature Assemblies.

Students can go through AP State Board 9th Class Biology Notes Chapter 11 Bio Geo Chemical Cycles to understand and remember the concept easily.

AP State Board Syllabus 9th Class Biology Notes Chapter 11 Bio Geo Chemical Cycles

→ The cycles that involve the flow of nutrients on earth involve the flow of nutrients on earth from the environment to organisms and back through certain pathways are known as biogeochemical cycles.

→ The interaction between the biotic and abiotic components of the biosphere consists of the transfer of matter and energy.

→ Biogeochemical pathways determine the path of transfer of matter on earth.

→ Water is a universal solvent and essential for various reactions to take place within a living cell

→ Nearly 97% of all the water on the earth is in the oceans and so only about 3% is freshwater.

→ Water participates in many biochemical mechanisms, including photosynthesis, digestion, and cellular respiration.

→ Water provides hydrogen and oxygen that form an integral part of basic organic compounds of life.

→ About 78% of nitrogen is present in the atmosphere, but plants and animals can not directly use it

→ A number of bacteria and blue-green algae are known to be able to fix atmospheric nitrogen into compounds in their own body e.g.: Rhizobium and Nitrosomonas.

→ The conversion of nitrates to ammonia by the denitrifying bacteria in the soil is known as nitrification.

→ Nitrogen compounds mainly nitrates or ammonium ions (NH₃) are taken up from soils by plants through a process known as assimilation.

→ The production of ammonia (NH₃) from nitrates and other nitrogenous compounds is called ammonification.

→ Solid (NO₃) is converted back to gaseous nitrogen (N₂) by a process called I denitrification.

→ Carbon dioxide or CO₂ makes up about 0.04% by volume of air.

→ Fixing of carbon in biological form takes place within plants and other organisms known as producers – in a process called photosynthesis.

→ Some gases present in the atmosphere such as carbon dioxide, carbon monoxide, methane, and water vapor trap heat from radiating back to space. This is known as the greenhouse effect

→ Excessive amounts of CO₂ and other greenhouse gases trap more amount of heat resulting in global warming.

→ Oxygen is found in the elemental form in the atmosphere to the extent of nearly 21 %.

→ Biological Oxygen Demand (BOD), represents the amount of oxygen needed by aerobic bacteria to decompose the waste.

→ Ozone is concentrated in a layer in the stratosphere, about 15.30 kilometers above the earth’s surface.

→ The ozone layer absorbs ultraviolet radiation from the sun, preventing it from reaching the planet’s surface.

→ Oxygen is also an essential component of most biological molecules like carbohydrates, proteins, nucleic acids, and fats.

→ The Montreal agreement in 1987 was to control and phase out the production and supply of ozone-depleting chemicals specifically chlorofluorocarbons (CFCs).

→ Water cycle or Hydrological cycle: It ¡s a process of constantly recycling water.

→ Nitro gen cycle: In this cycle nitrogen is converted from its inert atmospheric molecular form (N₂) into a form that is useful in biological processes.

→ Nitrogen fixation: It is the conversion of atmospheric nitrogen gas into ammonium and nitrates.

→ Nitrification: It is the conversion of nitrates into ammonia by the denitrifying bacteria in the soil.

→ Assimilation: It is the intake of nitrogen compounds mainly as nitrates or ammonium ions (NH) by plants.

→ Ammonification: It is the production of ammonia from nitrates and other nitro generous compounds.

→ Denitrification: It is the conversion of solid nitrate (NO₃) to gaseous nitrogen (N₂)from animal and plant cells.

→ Carbon cycle: It is the movement of carbon from one component to other components of the ecosystem which ¡s including both living organisms and the abiotic environment.

→ Greenhouse effect: Gases present in the atmosphere such as carbon dioxide, carbon monoxide, methane, and water trap heat from radiating back to space.

→ Global warming: Increase in temperatures of the earth due to the release of more amount of carbon dioxide and other greenhouse gases.

→ Oxygen cycle: Oxygen from the atmosphere is used up mainly by the processes, combustion, respiration and in the formation of oxides of elements like nitrogen, iron, etc., oxygen returns to the atmosphere through photosynthesis.

→ Precursor: A person or thing that comes before.

→ Condensation: The process of a gas changing to a liquid.

→ Precipitation: A chemical process in which solid material is separated from a liquid.

→ Soot: A black powder that is produced when wood, coal, etc. is burnt.

→ Ozone Depletion: Ozone is a molecule containing three oxygen atoms. Certain industrial processes and consumer products result in the emission of ozone-depleting substances into the atmosphere.

→ Though we usually think of oxygen as being necessary to live in the process of respiration, It might be of interest to you to learn that some forms of life, especially bacteria, are poisoned by elemental oxygen. In fact, even the process of nitrogen-fixing by bacteria does not take place in the presence of oxygen.

→ Vladimir Vernadsky:

• The founder of biogeochemistry was Russian scientist Vladimir Vernadsky whose 1926 book ‘The biosphere’ in the tradition of Mendeleev, formulated a physics of the earth as a living whole.
• Vernadsky distinguished three spheres, where a sphere was a concept similar to the Rieman concept of a space-phase.
• He observed that each sphere had its own laws of evolution and that the higher spheres modified and dominated the lower.

Students can go through AP State Board 9th Class Social Studies Notes Chapter 5 Biosphere to understand and remember the concept easily.

AP State Board Syllabus 9th Class Social Studies Notes Chapter 5 Biosphere

→ The Earth is a unique planet that has life thriving on it

→ Air, water, and moderate temperature have made life possible on the earth.

→ AH, forms of life have an integral connection with the land, air, water, and sunshine around them.

→ Many forms of life are symbiotic that is they live by exchanging essential substances with each other.

→ Plants are the primary food producers.

→ Any disturbance in the cycle of life can create an ecological crisis.

→ Since all living and non-living things on earth are in one way or the other connected to each other, change affecting one, in due time affects all others too.

→ Natural vegetation is generally classified into three broad categories.
(a) Forests in areas of sufficient rainfall and sunshine.
(b) Grasslands regions of moderate rains.
(c) Shrubs in dry regions.

→ The thick forests which occur in the regions near the equator and close to the tropics are called tropical rainforests (or) tropical evergreen forests.

→ The forests in which trees shed their leaves and occur in the regions i&htch experience seasonal changes are called Tropical Deciduous Forests.

→ The forests which are located in the mid latitudinal coastal region are called the temperate Evergreen Forests.

→ The forests in which trees shed their leaves in the dry season and are located in higher latitudes are called Temperate Deciduous Forests.

→ The forests which are located in the west and southwest margins of the continents are called the Mediterranean Vegetation.

→ The trees which can be seen in the higher altitudes, in which tall softwood evergreen trees are grown are called Coniferous Forests.

→ The grasslands that grow on either side of the equator and extend to the tropics are called Tropical grasslands.

→ The thorny vegetation found in the dry desert-like regions is called Thorny bushes. The mosses; lichens and very small shrubs found in polar regions are called Tundra type of vegetation.

→ The building of knowledge of the environment is an essential part of human being’s interaction with the natural world.

→ The increase in population creates great pressure on earth as well as its resources.

→ The immense human industrial activity has had a profound impact on the air; water and the land around us.

→ The burning of fossil fuels releases large quantities of carbon dioxide and other chemicals that cause acid rains.

→ The burning of fossil fuels, release of enormous amounts of waste materials contaminate the air, water, and soil.

→ The cumulative impact of pollution poisons our environment which leads to global warming.

→ The extra radiation received at the earth’s surface produces the greenhouse effect The Greenhouse effect in simple terms is the property of the atmosphere, which permits sunlight rather easily and releases that heat with great difficulty.

→ The fertilizers and pesticides used in agriculture eventually remain in the soil and also mix with water and result in contamination of water and soil Urbanisation causes a number of environmental problems.

→ Food chain: It is a complex phenomenon in which one kind of life becomes the food for another kind and so on.

→ Hardwood trees: These are the trees that yield hardwood necessary for making furniture, doors, and windows, etc.

→ Acid rains: Acid rains are caused by the mingling of acid particles of the atmosphere with rain increasing the acid content of rainwater.

→ Ecological crisis: Any disturbance in the cycle of life that goes on can create what s called an ecological crisis’.

→ Tundra: Tundra ¡s a biome where tree growth is hindered by low temperatures and short growing seasons.

→ Global warming: The increase in temperature of the earth’s atmosphere that is caused by the impact of pollutants especially carbon dioxide in the atmosphere.

→ Fossil / Fuel: The remains of animals I plant, which had turned into rock.

→ Steppe: A large land of grass with few trees here and there.

→ Biosphere: The separate sphere that constitutes countless forms of life from microscopic bacteria to great Banyan trees and animals like elephants, tigers, and blue whales and of course human beings is called Biosphere.

→ Eutrophication: An increase in the rate of supply of organic matter in an ecosystem.

→ Herbivores: The plant-eating animals are called herbivores.

→ The greenhouse effect: The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases and is radiated in all directìons.

→ Kyoto Protocol:
A conference was held in the city of Kyoto in Japan under United Nations Organization in December 1997 to protect mother earth from global warming. The countries that attended realized the effect of Green House Gases and signed a declaration called the Kyoto Protocol. The main aim of this is to bring down the release of Green House Gases to less than 5.2%. According to this declaration, this aim should be achieved between 2008-2012.

→ Approximately 13-15 tonnes of effluents and sewage water reach Kolleru lake daily from its nearby towns and villages.

→ One study found that the radiation released by cell phone towers affects the life of honey bees. This leads not only to a scarcity of honey but also affects pollination, biodiversity, and here agricultural products.

Students can go through AP State Board 8th Class Social Studies Notes Chapter 13 The Indian Constitution to understand and remember the concept easily.

AP State Board Syllabus 8th Class Social Studies Notes Chapter 13 The Indian Constitution

→ A Constitution is a set of rules.

→ The Indian Constitution was drafted under very difficult circumstances.

→ Everyone would be equal before the law.

→ The British too had introduced some basic institutions of democratic rule in India.

→ The Constitution was drafted by an assembly of elected representatives called the Constituent Assembly.

→ We can understand our Constitution by reading the views of some of our major leaders, on our Constitution.

→ Republic means the head of the state is an elected person and not a hereditary position as in a kingdom.

→ Our Constitution does not promise equality in all respects but it seeks to ensure that all people will enjoy the same status.

→ Our country has a federal system.

→ The central government has 2 houses – Lok Sabha and Rajya Sabha.

→ Our country has a three-level democracy.

→ The Constitution also provides for some independent institutions to guard the Constitution.

→ The Constitution is a living and changing document.

→ Monarchy: Rule by a monarch

→ Representative: Typical of a class or group

→ Discrimination: Unfair treatment of different categories of people on grounds of race, sex, etc.

→ Autonomous: Self-governing

→ Constitution: A body of principles according to which a state or organization is governed

→ Sovereign: A king or queen who is the supreme ruler of a country

→ Federal system: The main social system in medieval Europe, in which a person worked for a lord in exchange for land

→ Provisional: For the present time but likely to change, temporary.

→ Draft: A preliminary version of a piece of writing

→ Republic: A state in which power is held by the people and their elected representative and which has a President rather than a king or queen

→ Secular: Not religious or spiritual

→ Fraternity: Friendship and shared support within a group

→ Amendment: A minor improvement

Students can go through AP State Board 9th Class Biology Notes Chapter 10 Soil Pollution and Functions to understand and remember the concept easily.

AP State Board Syllabus 9th Class Biology Notes Chapter 10 Soil Pollution

→ Our environment is composed of the atmosphere, earth and water.

→ The interaction of the atmosphere, lithosphere, hydrosphere and biosphere is continuing for years together.

→ Soil is one of the marvellous products of nature and without which there would be no life.

→ Soil formation is a long and complex process and it can take 100 to 10,000years to create one inch of topsoil

→ Crop quality directly depends on the quality of the agricultural soil in which it is grown.

→ The soil properties can be divided into three major categories. Physical, chemical and biological properties.

→ Soil consists of nutrients necessary for plants growth such as nitrogen, phosphorus and potassium.

→ The pH of the soil is important in determining the type of vegetation that will grow in the soil and the type of organisms that will live there.

→ Soil is the most abundant and diverse ecosystem on the earth.

→ Soil microbes convert organic forms of elements to their inorganic forms and liberate carbon dioxide, ammonia etc., by a process known as mineralization.

→ Fertility of soil is closely associated with the properties of soil and is defined by its capacity to hold water and nutrients and supply them to plants when they need them, independent of direct application of nutrients.

→ Proper soil fertility management is very important for successful crop production and farming.

→ The waste generated from various sources can be categorized into two types like biodegradable waste and non-biodegradable waste.

→ Decomposition is the process of materials being digested and broken down into simpler substances making nutrients more available to plants.

→ Soil or land pollution can be understood as the addition of substances that adversely affect the quality of soil or its fertility.

→ On the basis of sources of pollutants, soil pollution can be classified into three categories.

1. Agricultural soil pollution
2. Soil pollution by industrial effluents and solid wastes
3. Pollution due to urban activities.

→ A soil pollutant is any factor that deteriorates the quality, texture and mineral content of the soil or which disturbs the biological balance of the organisms in the soil.

→ Pesticides not only have a toxic effect on humans and animals but also decrease the fertility of the soil

→ The process of increasing the concentration of chemicals through the food chain is known as biomagnification.

→ Solid waste may be defined as the organic and inorganic waste produced by various activities of the society which have lost their value to the first user.

→ Solid waste on the basis of its sources of origin can be classified as municipal solid waste, hazardous solid waste and infectious solid waste.

→ Soil erosion occurs when the weathered soil particles are dislodged and carried away by wind or water.

→ Forests and grasslands are an excellent binding material that keeps the soil intact

→ Urban activities generate large quantities of city wastes including several biodegradable materials.

→ If solid waste is left uncollected and decomposed, they cause problems like clogging of drains, the barrier to the movement of water, foul smell, increased microbial activities etc.

→ To prevent soil pollution, we can limit construction in sensitive areas.

→ In general, we would need less fertilizer and fewer pesticides if we could all adopt the four R’s: Reduce, Reuse, Recycle and Recover.

→ Incineration of wastes is expensive and leaves a huge residue and adds to air pollution.

→ Pyrolysis is a process of combustion in absence of oxygen or the material burnt under a controlled atmosphere of oxygen.

→ Bioremediation means using a biological remedy to reduce or clean up contamination.

→ We can conserve soil by planting trees, terraces, no-till farming, contour ploughing, crop rotation, soil pH, watering the soil, salinity management, soil organisms and indigenous crops.

→ Atmosphere: The gaseous envelope surrounding the earth constitutes the atmosphere.

→ Lithosphere: Solid rocky layer covering the entire surface of the planet.

→ Hydrosphere: Contains all of the earth‘s bodies of water.

→ Biosphere: All the life-supporting zones on earth are together called the biosphere.

→ Topography: It ¡s the shape or configuration of the land represented on a map by contour lines.

→ Parent material: Any type of substance or material which undergoes some process to produce another material.

→ Weathering: Breakdown of bigger rocks into smaller mineral particles.

→ Thawing: The process whereby heat changes something from a solid to a liquid.

→ Crumb: A very small quantity of something.

→ Leaching: To be removed from soil by water passing through it.

→ Stench: A strong, very unpleasant smell.

→ Trash: Things that we throw away because we no longer want or need them.

→ Smelt: To heat and melt ore.

→ Ooze: The liquid flows from the place slowly.

→ Clog: To block or become blocked.

→ Inundate: To cover an area of land with a large amount of water.

→ Dire: Very serious.

→ Pyrolysis: It ¡s a process of combustion in absence of oxygen or the material burnt under a controlled atmosphere of oxygen.

→ Incineration: To burn substance until it is completely destroyed at high temperature.

→ Omnipresent: Present everywhere.

→ Tillage: The process of preparing and using land for growing crops.

→ Abode: Living place.

→ Gophers: Animal that lives in holes in the ground.

→ Soil fertility: The soil containing rich nutrients and is suitable for plants to grow.

→ Mineralization: It ¡s the process of converting organic forms of elements to their inorganic forms by soil microbes liberating CO₂, NH₃, sulphate, phosphate.

→ Biogeochemical cycle: The cycle that involves the flow of nutrients on earth from the environment to organisms and back through certain pathways are known as the biogeochemical cycle.

→ Biodegradable waste: Substances that can be degraded by microbes into harmless and non-toxic substances.

→ Non-biodegradable waste: Substances that cannot be easily degraded.

→ Soil erosion: Loss of top layers of soil by wind or water ¡s known as soil erosion.

→ Biomagnification: The process of increasing the concentration of toxic chemicals through the food chain.

→ Bioremediation: It means to use a biological remedy to reduce or clean up soil contamination.

→ Soil pollution: Soil pollution is defined as the build-up in soils of persistent toxic compounds, chemicals, salts, radioactive materials, or disease-causing agents, which have adverse effects on plant growth and animal health.

→ Organic soil: Soil that contains 30% or more organic matter (residues of dead plants and animals) is considered organic soil.

→ Abate: Reduce

→ Mycorrhiza: It is the symbiotic association that is taking place between a fungus and the roots of a plant.

→ Fragility: Easily broken or damaged.

→ Subtle: Not very noticeable.

→ In one acre of land where the topsoil is eight inches thick nearly five and a half tons of Bacteria are present. 50,000 Earthworms are also present in it.

→ James Hutton (1726 – 1797):
James Hutton: Father of Modern Georgy

• James Hutton was a Scottish geologist, physician, chemical manufacturer, naturalist and experimental agriculturalist
• Hutton‘s work established geology as a proper science, and thus he is often referred to as the father of modern geology.
• He recognized that the history of the earth could be determined by understanding how processes such as erosion and sedimentation work in the present day.
• He is also credited as the first scientist to publicly express the earth was alive and should be considered a superorganism.

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 9th Class Social Studies Notes Chapter 4 Atmosphere to understand and remember the concept easily.

AP State Board Syllabus 9th Class Social Studies Notes Chapter 4 Atmosphere

→ The atmosphere is a sea of gases surrounding the earth.

→ The atmosphere consists of nitrogen (78%), oxygen (21%) and argon, neon, carbon dioxide, methane, ammonia and ozone in a very small percentage.

→ The fine dust particles or particulates can change atmospheric conditions and are beneficial to life on earth.

→ On the basis of chemical composition, the atmosphere is divided into two broad layers. They are 1) Homosphere 2) Heterosphere.

→ The Homosphere consists of three thermal layers as Troposphere, Stratosphere and Mesosphere.

→ The Heterosphere consists of two thermal layers called Thermosphere and Exosphere.

→ The gas molecules in the air constantly push each other or any other object that comes their way. This push affects them exert together on any other object is described as Air pressure.

→ When air is hot the pressure becomes low and when it is cool air pressure increases.

→ Wind flows from high-pressure areas to low-pressure areas.

→ The low-pressure belt at the earth’s surface around the equator is called the equatorial low-pressure belt or the Inter-Tropical Convergence Zone.

→ Because of the impact of Earth’s rotation on its own axis, the winds move slightly to the right in the northern hemisphere and to the left in the southern hemisphere. This effect is called the Coriolis effect

→ Depending upon the wind speed, their features, their directions, the way they occur, winds are classified into three types. They are Planetary winds, Seasonal winds and Local winds.

→ The winds that blow continuously and regularly above the world pressure belts are known as Planetary winds.

→ The winds in low latitudes that seasonally change direction between winter and summer are called Seasonal winds.

→ The winds that blow due to local variation in the temperature and pressure, and influence a very small area are called Local winds.

→ Chinook and Loo are hot and dry local winds.

→ Mistral Puna and Pampero are cold local winds.

→ Climate is a description of the average atmospheric conditions for areas over a long period of time.

→ The daily state of the atmosphere at a particular time and place is called weather.

→ Temperature, pressure, wind, humidity and precipitation are called the elements of weather.

→ The amount of water vapour in the atmosphere is called humidity.

→ The relative humidity is the ratio between the maximum water vapour that the air can hold at a given temperature and pressure and the actual amount of water vapour it holds at any given time.

→ If the atmosphere has 100% relative humidity, it is known as saturation level

→ When relative humidity exceeds 100 per cent the excess of water vapour present in the atmosphere gets condensed and forms as minute droplets of water.

→ With condensation, the droplets get heavy and fall to the ground as precipitation in the form of rain, snow, hail etc.

→ On the basis of origin, rainfall may be classified into three main types.
They are:

1. Convectional rainfall
2. Orographic rainfall and
3. Cyclonic rainfall

→ Convectional currents: The transfer of heat by the mass movement of heated particles into an area of cooler fluid.

→ Inter-Tropical Convergence Zone: The low-pressure belt around the equator is called the Equatorial low-pressure belt or the Inter-Tropical Convergence Zone.

→ Coriolis effect: Because of the impact of Earth’s rotation on its own axis the winds move slightly to the right towards the east in the northern hemisphere and to the left, i.e. towards the west in the southern hemisphere. This effect is called the Coriolis effect.

→ Relative Humidity: The amount of water vapour in the air.

→ Leeward side: The other side of the mountain receives less rainfall.

→ Tropical cyclones: Warmcore vortex circulation of tropical origin with a small diameter often of an approximately circular shape are called tropical cyclones.

→ Sleet: Wet, partly melted falling snow.

→ Chinook: The winds that move down the Rockey Mountains in the U.S.A – Canada and part of North America are known as Chinook.

→ Orographic Rainfall: The rain that occurs when the moist wind is forced to rise over mountains or other elevation in its path is called Orogenic rainfall (or) Orographic rainfall.

→ Loo: The hot and dry winds that blow in the plains of northern India from west to east in the months of May and June are called Loos.

→ Atmosphere: The thin layer of air that surrounds the earth is the atmosphere (or) The atmosphere is a sea of gases surrounding the Earth.

→ NASA: National Aeronautics and Space Administration – the space agency of the U.S.A.

→ Particulates: The fine dust particles in the atmosphere are called particulates.

→ Homosphere: The layer of the atmosphere which consists of gases like Nitrogen, Oxygen, Argon and Carbon dioxide.

→ Heterosphere: The layer which has heterogeneous composition and which is above 90 km of the atmosphere is called heterosphere.

→ Wind: The air that moves from areas of higher pressure to areas of lower pressure, is called wind.

→ Breeze: If the air that moves at a slow pace and we feel comfortable in it, is called a breeze.

→ Gust: The wind that comes in a short and fast burst is called a gust.

→ Storm: The wind that comes very fast and blows things around is called a storm.

→ Planetary winds: The winds that blow constantly, continuously, regularly above the world pressure belts are known as planetary winds.

→ Mistral: The most famous cold wind that blows from the Alps over France towards the Mediterranean sea is called Mistral.

→ Climate: The average atmospheric condition for areas over a long period of time is called the atmosphere.

→ Dew point: The critical temperature at which saturation level of humidity is reached is called a dew point.

→ Convectional Rainfall: The rainfall that occurs when moist air over the heated ground becomes warmer than the surrounding air and is forced to rise, expand, cool and yield some of its moisture, is called Convectional rainfall.

→ Cyclonic rainfall: The rainfall that is associated with the passage of a cyclone or depression is called Cyclonic rainfall.

→ Hygrometer is an instrument that measures the water vapour content (humidity) of the air.

Students can go through AP State Board 8th Class Social Studies Notes Chapter 12 Freedom Movement in Hyderabad State to understand and remember the concept easily.

AP State Board Syllabus 8th Class Social Studies Notes Chapter 12 Freedom Movement in Hyderabad State

→ Hyderabad was an important princely state of South India under British paramountcy.

→ It was ruled by the Nizams who were initially, provincial governors of the Mughal emperors.

→ Mullah Abdul Qayyum of Hyderabad became a great champion of the Congress.

→ In the year 1892 Arya Samaj was established in Hyderabad, which has credited many leaders to the nationalist movement in Hyderabad.

→ The Nizams actually discouraged the setting up of private Telugu medium schools.

→ In 1924 Madapati Hanumantha Rao and others formed the Andhra Jana Sangham.

→ The leaders of various sections decided to unite into one large organization and thus AMS was formed in 1930.

→ Later the radical elements gained leadership and a new movement of the peasants
started.

→ Enthused by the response of the youth of the state, the nationalists of Hyderabad had set up the Hyderabad State Congress in 1938.

→ in 1942 they started Satyagraha in tune with the National Quit India Movement.

→ From 1929, Ryot Sangams were established.

→ The movement was transformed in 1947-48 into a broad anti-Nizam and anti-feudal struggle demanding the merging of Hyderabad with independent India.

→ The fanatic Muslim enthusiasts formed Ittehadul Muslimeen, an organization to protect the Muslim domination of Hyderabad state and Nizam rule.

→ In 1947, the Nizam was Osman AiiKhan.

→ Hyderabad was finally integrated into Indian Union in September 1948.

→ Flrnianas: Orders issued by the rulers especially Muslim rulers

→ Vettel: Making some people work for no wages (slavery)

→ Feudal system: System of landlords

→ Subordinate kings: The kings under an emperor or a Samrat, enjoying liberty by paying some annual tribute

→ Legitimate rights: Rights that are guaranteed by law

→ Guerrilla squad: A group of armed people who attack all of a sudden

→ Jagirdars: Owners of Jagirs

→ Representative Government: A government that is run by the elected or nominated members

Students can go through AP State Board 8th Class Social Studies Notes Chapter 11B National Movement: The Last Phase 1919-1947 to understand and remember the concept easily.

AP State Board Syllabus 8th Class Social Studies Notes Chapter 11B National Movement: The Last Phase 1919-1947

→ Gandhiji arrived in India in 1915 from South Africa. He was already a respected leader known internationally.

→ His earliest interventions were in local movements in Champaran and Kheda.

→ He did not associate with any Congress faction. He built his own political program and space in nationalist politics.

→ Muslim League was formed in 1906 and Hindu Mahasabha in 1915.

→ During Rowlatt Satyagraha the participants tried to ensure that Hindus and Muslims were united in the fight against British rule.

→ The Non-Cooperation Movement gained momentum through 1921-22.

→ Guntur District was at the center of nationalist activity and the participation was very widespread.

→ Sometimes people thought of Gandhiji as someone who could help them overcome their misery and poverty.

→ On March 13th, 1930 Gandhiji led his March to Dandi village to break the government salt laws. A wave of enthusiasm swept the country.

→ The combined struggles of the Indian people bore fruit when the Government of India Act of 1935 prescribed provincial autonomy.

→ Subhash Chandra Bose organized the Indian National Army (INA) with the cooperation of Rash Bihari Bose in Burma and Andamans.

→ The period after 1940 was characterized by intensive activities of radical organizations.

→ Louis Mountbatten, who was appointed Viceroy in early 1947 was not able to resolve the differences between the Muslim League and the Congress party.

→ Independence is our strength. Partition is our failure.

→ Nationalism: Patriotic feeling often to an extensive degree

→ Secular: Not religious or spiritual

→ Terrorist: A person who uses violence and intimidation in the attempt to achieve political aims unofficially

→ extremism: Holding extreme political or religious views

→ Satyagraha: True anger. It was introduced and led by Gandhiji in our Independence movement.

→ Non-Cooperation: Not rendering co-operation to the government by not accepting their policies, not obeying their orders, and not paying taxes, etc.

→ Civil Disobedience: Refuse to be obedient by the people of a nation

→ Subcontinent: The land or a country that has all the characteristics of a continent

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.