CBSE Class 10

On this page, you will find NCERT Class 10 History Chapter 1 Notes Pdf free download. CBSE Class 10 Social Science Notes History Chapter 1 SST The Rise of Nationalism in Europe will seemingly, help them to revise the important concepts in less time.

The Rise of Nationalism in Europe Class 10 Notes Social Science History Chapter 1

CBSE Class 10 History Chapter 1 Notes Understanding the Lesson

1. During the nineteenth century, nationalism emerged as a force which brought about sweeping changes in the political and mental world of Europe. The final result of these changes was the emergence of the nation-state in place of the multinational dynastic empire of Europe.

2. The first clear expression of nationalism came with the French Revolution in 1789. France was a full-fledged territorial state in 1789 under the rule of an absolute monarch. The political and constitutional changes that came in the wake of the French Revolution led to the transfer of sovereignty from the monarchy to a body of French citizens.

3. A new French flag, the tricolour, was chosen to replace the former royal standard. The Estates-General was elected by the body of active citizens and renamed the National Assembly. New hymns were composed, oaths taken and martyrs remembered, all in the name of the nation.

4. The news of the events in France reached the different cities of Europe. As a result, people in these cities began setting up Jacobin clubs. Their activities and campaigns prepared the way for the French armies which moved into Holland, Belgium, Switzerland and Italy and spread there the idea of nationalism. The cities like Brussels, Mainz, Milan and Warsaw also welcomed the French armies. They began to view the French armies as harbingers of liberty.

5. There were no nation-states in mid-eighteenth-century Europe. Germany, Italy and Switzerland were divided into several kingdoms. Eastern and central Europe were under autocratic monarchies within the territories of which lived diverse peoples. Often, they spoke different languages and belonged to different ethnic groups. The only tie binding these diverse groups together was a common allegiance to the emperor.

6. The continent of Europe was dominated by the landed aristocracy. Although it constituted a small group, it was very powerful. The majority of the population was made up of the peasantry. With industrialization, new social groups which included a working-class population, and middle classes made up of industrialists, businessmen, professionals etc. came into being. However, the educated, liberal middle classes began to think of ways to abolish aristocratic privileges.

7 . Ideas of national unity in early-nineteenth-century Europe were closely allied to the ideology of liberalism. For the new middle classes liberalism stood for freedom for the individual and equality of all before the law. In the economic sphere, liberalism stood for the freedom of markets and the abolition of state-imposed restrictions on the movement of goods and capital.

8. Napoleon, who ruled France for more than a decade, was defeated by the collective power of Britain, Russia, Prussia and Austria. Afterwards, the representatives of these European powers met at Vienna in 1815 and drew up the treaty of Vienna with the object of undoing most of the changes that had come about in Europe during the Napoleonic wars. The main intention was to restore the monarchies and create a new conservative order in Europe.

9. Conservative regimes set up in 1815 were autocratic. They did not tolerate criticism and dissent and imposed censorship on newspapers, books, plays and songs that reflected the ideas of liberty and freedom. Many liberal-nationalists, therefore, went underground. Secret societies in many European states began to train revolutionaries who aimed at the creation of nation-states.

10. One such revolutionary was Giuseppe Mazzini who hailed from Italy. He became a member of the secret society of the Carbonari. Afterwards he founded two more underground societies whose members were young men from Poland, France, Italy and the German states.

11. Revolutions led by the liberal-nationalists spread in many regions of Europe. The first upheaval took place in France in July 1830 as a result of which the Bourbon kings were overthrown and a constitutional monarchy with Louis Philippe as its head was installed. The July Revolution sparked an uprising in Brussels which led to Belgium breaking away from the United Kingdom of the Netherlands.

12. The growth of revolutionary nationalism in Europe gave rise to a struggle for independence amongst the Greeks. In 1832, the Treaty of Constantinople took place which finally recognized Greece as an independent nation.

13. Culture also played an important role in creating the idea of the nation. Art and poetry, stories and music helped express and shape nationalist feelings. Language too contributed a lot in the development of nationalist sentiments.

14. With an enormous increase in population in the nineteenth century Europe led to widespread poverty in town and country. In 1848, the poor people of Paris came out on the roads forcing Louis Philippe to flee. A National Assembly proclaimed a republic, granted suffrage to all adult males above 21, and guaranteed the right to work. National workshops to provide employment were set up.

15. Revolutions were also started by the educated middle classes belonging to Germany, Italy, Poland and the Austro-Hungarian Empire. They took advantage of the growing popular unrest to push their demands for the creation of a nation-state on parliamentary principles. Monarchs now began to realize that cycles of revolution and repression could only be ended by granting concessions to the liberal-nationalist revolutionaries.

16. As nationalist feelings were widespread among middle-class Germans, in 1848 they tried to unite the different regions of the German confederation into a nation-state governed by an elected parliament. Prussia took on the leadership of the movement for national unification. Its Chief Minister, Otto von Bismarck played an important role in this process. After the completion of the unification, the Prussian King, William I was proclaimed German Emperor in January 1871.

17. Like Germany, Italy too had a long history of political fragmentation During the middle of the nineteenth century, Italy was divided into seven states, of which only one, Sardinia-Piedmont was ruled by an Italian princely house. Even the Italian language had not acquired one common form.

18. Chief minister of Sardinia-Piedmont named Cavour led the movement to unify the regions of Italy.

19. Through a tactful diplomatic alliance with France engineered by him, Sardinia-Piedmont succeeded; in defeating the Austrian forces in 1859. Apart from regular troops, a large number of armed volunteers under the leadership of Giuseppe Garibaldi joined the fray. In 1860, they marched into South Italy and the Kingdom of the Two Sicilies and succeeded in driving out the Spanish rulers. In 1861, Victor Emmanuel II was proclaimed king of United Italy.

20. In Britain, the formation of the nation-state was not the result of a sudden upheaval or revolution.

21. It was the result of a long-drawn-out process. The new British nation was forged through the j propagation of a dominant English culture. The symbols of the new Britain – the British flag, the j national anthem, the English language etc. were actively promoted.

22. Artists in the eighteenth and nineteenth centuries began to represent a country as if it were a person.

23. Nations were then portrayed as female figures. The female form that was chosen to personify the nation did not stand for any particular woman in real life; rather it sought to give the abstract idea of the nation as a concrete form. Thus, the female figure became an allegory of the nation. In France, she was christened Marianne which underlined the idea of a people’s nation. Similarly, Germania; became the allegory of the German nation.

24. By the last quarter of the nineteenth-century nationalism no longer retained its idealistic liberal-democratic sentiment of the first half of the century, but became a narrow creed with limited ends. During this period, nationalist groups became increasingly intolerant of each other and ever ready to go to war.

25. It was this sentiment that led Europe to disaster in 1914 when the First World War broke out. However, the 19th century also witnessed the growth of anti-imperial movements in different parts of the world.

The Rise of Nationalism in Europe Class 10 CBSE Notes Important Terms

Absolutist: The term refers to a form of monarchical government that was centralized, militarized and repressive.

Utopian: A vision of a society that is so ideal that it is unlikely to actually exist.

Plebiscite: A direct vote by which all the people of a region are asked to accept or reject a proposal.

Suffrage: The right to vote.

Conservatism: A political philosophy that stressed the importance of tradition, established institutions and customs, and preferred gradual development to quick change.

Feminist: Awareness of women’s rights and interests based on the belief of the social, economic and political equality of the genders.

Ideology: System of ideas reflecting a particular social and political vision.

Ethnic: Relates to a common racial, tribal, or cultural origin or background that a community identifies with or claims.

Allegory: Expression of an abstract idea such as greed, envy, freedom, liberty through a person or a thing.

Feudalism: A social system that existed in Europe during the Middle Ages in which people worked and fought for nobles who gave them protection and the use of land in return.

Nationalism: Devotion for one’s own nation’s interests over those of all other nations.

Notes of History Class 10 Chapter 1 Time Period

1797: Italy invaded, beginning of Napoleonic wars

1804-15: Siberian Revolution against the Ottoman Empire

1815: Congress of Vienna

1821-29: Greek War of Independence against the Ottoman Empire

1830-31: Belgian Revolution

1830-31: Revolution in Poland and Lithuania

1846: Uprising in Greater Poland

1848: Nationalist revolts in Hungary, Italy and Germany

1859-61: Italy unified

1866-71: Germany unified

On this page, you will find Management of Natural Resources Class 10 Notes Science Chapter 16 Pdf free download. CBSE NCERT Class 10 Science Notes Chapter 16 Carbon and its Compounds will seemingly help them to revise the important concepts in less time.

CBSE Class 10 Science Chapter 16 Notes Management of Natural Resources

Management of Natural Resources Class 10 Notes Understanding the Lesson

1. Natural resources: The resources provided by the nature and utilised by human beings are called natural resources. Example: Soil, air, water, forests, wildlife, coal, petroleum, etc. Management of Natural Resources is necessary for their conservation and sustainable development.

2. Efforts for Environment Protection: There are international laws and regulations; National laws and acts creating awareness and National and international organisations working towards protecting our environment.

3. Ganga Action Plan: A multi-crore project came about in 1985 to improve quality of the water in the Ganga.

4. Coliform: A group of bacteria found in human intestines. Its presence in water indicates contamination by disease-causing microorganisms.

5. Survey for Coliform Count in 1993-1994: The results of survey done in 1993-1994 for finding total coliform in terms of MPN/100 mL is:
Minimum desired level 450 MPN/100 mL; Minimum level found in Rishikesh 600-650 MPN/100 mL; Maximum level found in Kannauj 1400 MPN/100 mL.

6. Pollution of the Ganga: The Ganga runs a course of 2500 km from Gangotri in the Himalayas to Ganga Sagar in the Bay of Bengal. It is getting polluted due to the flow of garbage, excreta, untreated sewage which are dumped into it. Also, human activities like bathing, washing of clothes and immersion of ashes or unbumt corpses, chemical effluents from industries increase its pollution load. This leads to toxicity which kills fish in large sections of the river.

7. The three R’s to save the environment: Reduce, Recycle and Reuse.

8. Reduce: Use less and not to waste any resource.

9. Recycle: Segregate the waste that can be recycled and make required things by using them,

10. Reuse: Use the things again and again.

11. Reuse is better than recycling: Reusing helps to save energy, so it is better than recycling.

12. Concept of sustainable development: Encourage forms of growth and development which helps to meet current basic human needs while preserving the resources for the needs of future generations. In this way economic development is linked to environmental conservation.

13. Need to Manage Natural Resources: The human population is increasing at a tremendous rate due to improvement in health care, so the demand for all resources is increasing at an exponential rate. Since the resources are limited, the management of natural resources is necessary, so that these will last for the generations to come. This management would help in equitable distribution of resources and reducing the damage being done to the environment.

14. Biodiversity Hot Spots: Forests are biodiversity hot spots. Number of species found in an area is one of the measures of biodiversity along with the range of different life forms (bacteria, fungi, ferns, flowering plants, nematodes, insects, birds, reptiles, etc.)

15. Result of loss in biodiversity: Experiments and field studies suggest that a loss of diversity may lead to a loss of ecological stability.

16. Stakeholder: A person having interest or concern for something is called as stakeholder. The various stakeholders for the conservation of forests are:

• Local People: Those who are dependent on forests for their survival.
• Forest Department: Government who owns the land and controls resources
• Industrialists: Those who use various forests
• Wildlife enthusiasts: Those who want to conserve nature

17. Efforts of Bishnoi community in Rajasthan: Bishnoi community of Rajasthan has religiously being protecting the environment. ‘Amrita Devi Bishnoi National Award for Wildlife Conservation’ is given by the Government in the memory of Amrita Devi Bishnoi, who in 1731 AD sacrificed her life along with 363 others for the protection of‘khejri’ trees in Khejarli village near Jodhpur in Rajasthan.

18. Sustainable Management: The management of forest resources wisely and judiciously to fulfil needs of present generation as well as future generations.

19. The Chipko Andolan (‘Hug the Trees Movement’): This movement for conservation of forests originated in a remote village called Reni in Garhwal Himalayas during the early 1970s when the women of the village clasped the tree trunks thus preventing the workers of logging contractor from felling the trees.

20. People’s Participation in the Management of Forests: In 1972, the West Bengal Forest Department failed in reviving the degraded Sal forests in the south-western districts of the state by methods of surveillance and policing. Complete alienation of the people from the administration led to movements by the Naxalites and into frequent clashes between forest officials.

21. Due to efforts of forest officer A.K. Baneijee, villagers were involved in the protection of 1,272 hectares of badly degraded Sal forest. Villagers were given employment in both silviculture and harvesting operations, 25 per cent of the final harvest, and allowed fuel wood and fodder collection on payment of a nominal fee in return of such help in protection. By 1983, the previously worthless Sal forests in Arabari forest range of Midnapore district underwent a remarkable recovery and were valued ? 12.5 crores with the active and willing participation of the local community.

22. Water as a Resource
Reasons for failure to sustain water availability underground:
Loss of vegetation cover, diversion for high water demanding crops, and pollution from industrial effluents and urban wastes.

23. Dams
Advantages of Dams:

• Ensure the storage of adequate water for irrigation and generating electricity.
• Canal systems leading from these dams can transfer large amounts of water great distances. Disadvantages of Dams:
• No equitable distribution of water.
• Large number of people displaced without compensation.
• Huge amount of public money is involved without giving proper benefits.
• Loss of biological diversity and deforestation.

24. Criticisms about large dams: They lead to

• Social problems: They displace large number of peasants and tribals without adequate compensation or rehabilitation.
• Economic problems: They swallow up huge amounts of public money without the generation of proportionate benefits.
• Environmental problems: They contribute enormously to deforestation and the loss of biological diversity.

25. Narmada Bachao Andolan (‘Save the Narmada Movement’): The movement started against the raising of the height of the Sardar Sarovar Dam on the river Narmada.

26. Water Harvesting: Watershed management emphasises scientific soil and water conservation in order to increase the biomass production.

27. Aim: To develop primary resources of land and water to produce secondary resources of plants and animals for use in a manner that will not cause ecological imbalance.

28. Benefits of Watershed management:

• Increases the production and income of the watershed community
• Mitigates droughts and floods
• Increases the life of the downstream dam and reservoirs.

29. Various ancient methods of water harvesting:

• Khadins, tanks and nadis in Rajasthan
• Bundhis in Madhya Pradesh and Uttar Pradesh
• Kulhs in Himachal Pradesh
• Eris (tanks) in Tamilnadu
• Kattas in Karnataka
• Bandharas and tals in Maharashtra
• Ahars and pynes in Bihar
• Ponds in the Kandi belt of Jammu region
• Surangams in Kerala,

30. Purpose of Water Harvesting:

• To recharge the ground water beneath.

31. Advantages of water stored in the ground:

• It does not evaporate.
• Spreads out to recharge wells and provides moisture for vegetation over a wide area.
• Does not provide breeding grounds for mosquitoes like stagnant water.
• It is relatively protected from contamination by human and animal waste.

32. Coal and Petroleum

• They are generally called fossil fuels.
• They are formed from the degradation of biomass millions of years ago.
• They will be exhausted in the future no matter how carefully we use them.
• Petroleum resources will last for about forty years while coal resources will last for two hundred years.
• They contain carbon, hydrogen, nitrogen and sulphur.
• They produce carbon dioxide, water, oxides of nitrogen and oxides of sulphur on being burnt.
• Carbon monoxide is formed instead of carbon dioxide, when they are burnt in insufficient amount of oxygen.
• The oxides of sulphur and nitrogen and carbon monoxide are poisonous at high concentrations and carbon dioxide is a greenhouse gas.
• Increase in amount of carbon dioxide is leading to global warming.

33. Ways to use resources judiciously:

• Taking a bus, public transport or walking/cycling instead of a private vehicle.
• Using LED bulbs in homes instead of normal bulbs.
• Taking the stairs instead of lift.
• Wearing an extra sweater on cold days instead of burning fossil fuels for warmth.

Class 10 Science Chapter 16 Notes Important Terms

Natural Resources: The stocks of nature such as air, water, soil, forests and wildlife. Biodiversity: The diversity of life forms present on Earth.

Sustainable Management: The judicious and wise use of natural resources to fulfil needs of present generation and preserving them for needs of the future generations.

Coliform: Group of gram negative, rod shaped bacteria found in polluted water and in human intestine. Coliform Count: Measure of pollution level of a water body on the basis of presence of coliform bacteria.

Silviculture: Practice of growing trees. Helpful in replenishment of forests.

Monoculture: A culture of single type of plant or tree in an area of forest.

Deforestation: Cutting down trees.

Afforestation: Growing or planting trees.

Reforestation: Growing or planting trees in a deforested area which previously had trees and vegetation.

On this page, you will find Our Environment Class 10 Notes Science Chapter 15 Pdf free download. CBSE NCERT Class 10 Science Notes Chapter 15 Our Environment will seemingly help them to revise the important concepts in less time.

CBSE Class 10 Science Chapter 15 Notes Our Environment

Our Environment Class 10 Notes Understanding the Lesson

1. Environment: Everything which surrounds us is environment. It may include living (biotic) and non-living (abiotic) components.

2. Biodegradable substances: Substances that can be slowly destroyed and broken down into very small parts by natural processes with the help of bacteria, fungi, etc. Example: Organic wastes like vegetable and fruit peels, dead plants and animals, etc.

3. Non-biodegradable substances: Substances which cannot be broken down or decomposed into the soil by natural agents are called non-biodegradable. Example: Plastics, polystyrene, metals, aluminium cans, toxic chemicals, paints, etc.

4. Problem due to Non-biodegradable substances: The non-biodegradable substances persist in the j environment for a long time as they are usually unreactive (inert) and may be harmful for the members of the ecosystem.

5. Same enzyme does not break-down everything (Reason for pollution by plastic):
Enzymes are highly specific in their action. Due to this specificity of the enzymes to act on a particular substrate only, many human-made materials like plastics are not broken down by the action of enzymes of bacteria or other saprophytes.
These materials are acted upon by physical processes like heat and pressure which makes them persistent for several thousand years.

6. Ecosystem: All the interacting organisms in an area together with non-living components form an ecosystem.

On the basis of their position or role in the ecosystem, the organisms are classified as:

1. Producers: The organisms which can synthesise their own food by the process of photosynthesis in presence of sunlight, i.e., all green plants, blue green algae, some photosynthetic bacteria, etc.

2. Consumers: Consumers feed on producers or other consumers to survive. They directly or indirectly depend on producers for their food.

3. Decomposers: The organisms which breakdown (decompose) the dead remains of plants and animals or convert complex compounds into simpler ones so that they go into the soil and are used up again by the plants are called decomposers. Example: Fungi and bacteria. Decomposers help in the replenishment of the natural resources.

4. Role of Decomposers:
Decomposers breakdown the dead remains and waste products of organisms i.e., complex organic substances into simple inorganic substances that go into the soil and are used up once more by the plants.

5. Food Chain: Food chain refers to an arrangement of different biotic groups in a sequence of energy transfer. It consists of a series of organisms feeding on one another.

6. Food web: In nature, the food chains are interconnected with each other forming a web-like pattern. This network of food chains is called a food web.

• Trophic level: Each step or level of the food chain where transfer of energy takes place is called trophic level.
• First Trophic level: Autotrophs (Producers)
• Second trophic level: Primary consumers (Herbivores)
• Third Trophic level: Secondary consumers (Small carnivores)
• Fourth Trophic level: Tertiary consumers (Larger carnivores)

7. Flow of energy between various components of the environment

• Green plants capture 1% of the sunlight that falls on their leaves.
• The flow of energy is unidirectional in a food chain.
• Ten Percent Law: About 90% of energy is used by the present trophic level in its life processes like respiration, digestion, etc. and only 10% of energy is transferred to the next trophic level.
  .
• Food chains generally consist of only three or four steps: Only 10% of energy is transferred to the next trophic level, so the loss of energy at each step is so great that very little usable energy remains after four trophic levels.
• There are generally a big population at lower trophic levels of an ecosystem. The population of the producers is the highest in a food chain.
• The relationship among organisms can be shown as a series of branching lines called a food web instead of a straight line as each organism is generally eaten by two or more other kinds of organisms which in turn are eaten by several other organisms.

8. Biological Magnification: The pesticides and other chemicals used to protect our crops from diseases and pests get either washed down into the soil or into the water bodies. They enter the food chain on being absorbed by the plants along with water and minerals from soil or on being taken up by aquatic plants and animals from the water bodies.

These get accumulated progressively at each trophic level as they are not degradable. The maximum concentration of these chemicals gets accumulated in human bodies as humans occupy the topmost trophic level in a food chain. This phenomenon is known as biological magnification. Due to this, our food grains, vegetables and fruits contain varying amounts of pesticide residues.
Ozone: Ozone (O₃) is a molecule formed by three atoms of oxygen.

9. Bad Ozone: The ozone present in the troposphere (lower parts of atmosphere) is harmful for plants and animals.

10. Good Ozone: The ozone present in the stratosphere (higher levels of the atmosphere) is beneficial as it shields the surface of the Earth from ultraviolet (UV) radiation of the Sun which is highly damaging to organisms and can cause skin cancer in human beings.

11. Formation of Ozone:
High energy UV radiation act on oxygen (O₂) molecule and split apart some molecular oxygen (O₂) into free oxygen (O) atoms. These oxygen atoms then combine with the molecular oxygen to form ozone.

12. Reason of Ozone Depletion:
Excessive use of synthetic chemicals like chlorofluorocarbons (CFCs) used as refrigerants and in fire extinguishers, caused ozone depletion in the upper atmosphere. In 1987, UNEP (United Nation Environment Programme) forged an agreement to freeze CFCs production at 1986 levels by all countries.

13. Ozone Hole: The decline of ozone layer thickness in Antarctica was first discovered in 1985 and was termed as Ozone Hole (thinning of ozone layer).

14. Management of Garbage:
Rapid industrialisation and the rise in demand of consumer goods have led to excessive garbage generation and problems of their disposal.

15. The methods of solid waste disposal are:

• Recycle: Non-biodegradable solid wastes like plastic, metal can be recycled.
• Reuse: Paper can be reused for making greeting cards, decorative articles, etc.
• Composting: Organic wastes filled into a compost pit can be converted into organic manure.
• Landfill: Wastes dumped in low lying area are compacted by rolling with bulldozers.
• Incineration: Burning wastes in incinerators.

16. Use of Disposable Paper cups: Instead of plastic cups, use of disposable cups made of clay called kulhads were suggested as an alternative. The use of kulhads on large scale results in loss of the fertile top soil. So, now disposable paper cups are being used instead of kulhads.

Class 10 Science Chapter 15 Notes Important Terms

Biodegradable substances: The substances which can be easily broken down into simpler substances by natural processes, e.g., wood, paper, etc.

Non-biodegradable substances: The substances which cannot be easily degraded into simpler substances by natural processes, e.g., plastics, DDT, etc.

Pollution: Any undesirable change in the physical, chemical or biological characteristics of air, water or soil is called pollution.

Ecosystem: The interaction of the living and non-living components of an area forms a unit called ecosystem.

Biotic: The living components of an ecosystem are called biotic. For example, predators, plants, parasites, etc.

Abiotic: The non-living components of an ecosystem are called abiotic. For example, temperature, humidity, etc.

Food chain: It is the sequence of organisms formed to transfer food energy by the act of eating or being eaten.

Food web: A network of food chains is called a food web.

Trophic level: Various steps in a food chain at which the transfer of energy takes place are called trophic levels.

Producers: The organisms which can synthesise their own food by the process of photosynthesis.

Consumers: The organisms which depend directly or indirectly on producers for their food requirements.

Decomposers: The organisms which break down the complex substances present in dead remains of plants and animals into simpler substances.

Biological magnification: The phenomenon in which the concentration of harmful toxicant goes on increasing at successive trophic levels, e.g., DDT.

On this page, you will find Sources of Energy Class 10 Notes Science Chapter 14 Pdf free download. CBSE NCERT Class 10 Science Notes Chapter 14 Sources of Energy will seemingly help them to revise the important concepts in less time.

CBSE Class 10 Science Chapter 14 Notes Sources of Energy

Sources of Energy Class 10 Notes Understanding the Lesson

Characteristics of a good fuel

• High calorific value (gives more heat per unit mass).
• Bums without giving out any smoke or harmful gases.
• Proper ignition temperature.
• Cheap and easily available.
• Easy to handle, safe to transport.
• Convenient to store.
• Burns smoothly.

Classification of sources of energy

1. On the basis of use

• Conventional sources of energy.
• Non-conventional sources of energy
• Conventional sources of energy are those which are used extensively and meet a major portion of our energy requirement.
  Examples:
  (a) Fossil fuels,(b) Thermal power plant,(c) Hydropower plant,(d) Biomass,(e) Wind energy.
• Non-conventional sources of energy are those which are not used as the conventional ones and meet our energy requirements only on a limited scale.
  Examples:
  (a) Solar energy,(b) Nuclear energy,(c) Tidal and wave energy,(d) Geothermal energy

2. On the basis of quantity available

• Renewable sources of energy
• Non-renewable sources of energy
• Renewable sources of energy are those which are inexhaustible i.e., which can be replaced as we use them and can be used to produce energy again and again.
  Examples:
  (a) Solar energy,(b) Wind energy
• Non-renewable sources of energy are those which are exhaustible and cannot be replaced once they have been used.
  Examples:  (a) Fossil fuel

Conventional sources of energy
1. Fossil fuels: Fossil fuels were formed millions of year ago, when plant and animal remains got buried under the Earth and were subjected to high temperature and pressure conditions.

Examples: Coal and petroleum
These are non-renewable sources of energy:

Pollution Caused by Fossil Fuels

• Released oxides of carbon, nitrogen and sulphur (acidic in nature) which causes acid rain that damages trees, plants, reduces fertility of soil.
• Produces large amount of CO₂ in the atmosphere which causes greenhouse effect leading to excessive heating of the Earth.

Controlling Pollution Caused by Fossil Fuels

• Increasing the efficiency of the combustion process.
• Using various techniques to reduce the escape of harmful gases and ashes into the surroundings.

2. Thermal Power Plant
A power plant which uses heat energy to generate electricity.

• Burning of fossil fuels produces steam to run turbines.
• Set up (power plants) near the coal and oil fields to minimise the cost of transportation and production.
• Transmission of electricity is more efficient.

3. Hydro Power Plants

• Dams are constructed to collect water flowing in high altitude rivers. The stored water has a lot of potential energy.
• When water is allowed to fall from a height, potential energy changes to kinetic energy, which
• rotates the turbines to produce electricity.

Advantages

• No environmental pollution
• Flowing water is a renewable source of electric energy.
• Construction of dams prevents flooding of rivers, provide water for irrigation.

Disadvantages

• Large areas of agricultural land, a vast variety of flora and fauna, human settlements get submerged in the water of reservoir formed by the dam.
• Large ecosystems are destroyed.
• Vegetation that submerged under water rots under anaerobic conditions and produces large amount of methane which is a greenhouse gas.
• Creates problems of satisfactory rehabilitation of displaced people.
• Dams are highly expensive to construct.
• Dams cannot be constructed on all river sites.

4. Biomass

The dead parts of plants and trees and the waste materials of animals are called Biomass.
(i) Wood: It is a biomass and used as a fuel for a long time.
Disadvantages

• Produces a lot of smoke on burning.
• Do not produce much heat.
• Thus by improvement in technology we can improve the efficiency of traditional sources of energy.
  For example, wood can be converted into much better fuel called charcoal.

(ii) Charcoal: When wood is burnt in a limited supply of air, then water and other volatile materials gets removed and charcoal is formed.

Charcoal is a better fuel than wood because

• it has a higher calorific value than wood.
• it does not produce smoke while burning.
• it is a compact fuel, easy to handle and convenient to use.

(iii) Cow dung: It is biomass but it is not good to burn cowdung directly as fuel because it

• produces a lot of smoke.
• does not burn completely, produces a lot of ash as residue.
• has low calorific value.
  by making biogas (or gobar gas) from cow dung, we get a smokeless fuel.

(iv) Biogas: It is mixture of gases produced during decomposition of biomass in the absence of oxygen.

• Methane is major component of biogas. Biogas contains 75% methane, carbon dioxide, hydrogen and hydrogen sulphide.
• Biogas is produced in a biogas plant using animal dung, sewage, crop residues, vegetable wastes, poultry dropping, etc.

Biogas plant: Construction and Working
The plant has dome like structure built with bricks. A slurry of cow dung and water is made in the mixing tank from where it is fed into the digester. The digester is a sealed chamber in which there is no oxygen. Anaerobic microorganisms that do not require oxygen, decompose or breakdown complex compound of cow slurry and produces methane, carbon dioxide, hydrogen and hydrogen sulphide.

Advantages of Biogas

• It is an excellent fuel as it contains upto 75% methane (CH₄).
• It burns without smoke.
•  Leaves no residue like ash in wood and coal burning.
• Heating capacity is high.
• It is also used for lighting.
• Slurry left behind is used as excellent manure rich in nitrogen and phosphorus.
• Safe and efficient method of waste disposal.

5. Wind energy

• Unequal heating of the landmass and water bodies by solar radiations generate air movement and causes wind to blow.
• Kinetic energy of the wind can be used:
  o to generate electricity by turning the rotor of the turbine, o to lift water from the well, o to run flour mills.
• But the output of a single windmill is quite small so a number of windmills are erected over a large area called wind energy farm.
• The minimum wind speed for windmill to serve as a source of energy is 15-20 km/per hour.

Advantages

• Eco-friendly
• Efficient source of renewable energy
• No recurring expenses for production of electricity.

Disadvantages

• Wind energy farms need large area of land.
• Difficulty in getting regular wind speed of 15-20 km/per hour.
• Initial cost of establishing wind energy farm is very high.
• High level of maintenance of blades of windmill.

Alternate or Non-conventional Sources of Energy
Day by day, our demand for energy is increasing, so there is a need for another source of energy.

Reasons for alternate sources of energy

• The fossil fuel reserves in the Earth are limited which may get exhausted soon if we use them at the current rate.
• Reduce the pressure on fossil fuels making them last for a much longer time.
• To reduce the pollution level and to save the environment.

(i). Solar Energy

• Sun is the ultimate source of energy.
• Energy obtained from the Sun is called solar energy.
• Energy received by the Earth per second per unit area from the Sun is known as solar constant.

Solar constant = 1.4 kJ/s/m² Solar energy devices: Devices using solar energy are:

• Solar cooker
• Solar cells
• Solar water heater
• Solar Cooker

Box Type Solar Cooker: It consists of a rectangular box which is made up of wood or plastic which is painted dull black.

• Inner walls of the box are painted black to increase heat absorption.
• Solar cookers are covered with glass plate and have mirror to focus the rays of the sun and achieve higher temperature. Glass plate traps solar radiation by greenhouse effect.
• Temperature inside the box increases 100°C-140°C in 2-3 hours.

Advantages

• Save precious fuel like coal, LPG, kerosene.
• Does not produce smoke.
• Nutrients of food do not get destroyed while cooking.
• Upto four food items can be cooked at the same time.
• Renewable
• Can be used in rural areas.

Disadvantages

• Solar cookers cannot be used at night.
• If the day sky is covered with clouds, even then solar cooker cannot be used.
• Direction of reflector of solar cooker changes from time to time to keep it facing the sun.
• Solar radiations are not uniform over the Earth’s surface.
• Cannot be used for frying or baking purpose.

(ii) Solar Cell

• Solar cells convert solar energy into electricity.
• A solar cell develops a voltage of 0.5-1 V and can produce about 0.7 W of electricity.
• A large number of solar cells are combined in an arrangement called solar cell panel.

Advantages

• Have no moving parts.
• Require little maintenance.
• Can work without any focussing device.
• Can be set up in remote and inacessible areas.

Disadvantages

• Manufacturing is expensive.
• Availability of special grade silicon for making solar cells is limited.
• Silver wire for interconnection of cells is expensive.

Uses of Solar Cell

• Artificial satellites and space probes use solar cells as the main source of energy.
• Radio, TV relay stations in remote locations use solar cell panels.
• Traffic signals, calculators and many toys are fitted with solar cells.

2. Energy from the Sea

3. Geothermal Energy

• ‘Geo’ means ‘earth’ and ‘thermal’ means ‘heat’.
• Geothermal energy is the heat energy from hot rocks present inside the earth.
• When underground water comes in contact with ‘hot spot’, steam is generated. Steam trapped in rocks is routed through pipes to a turbine and used to generate electricity.

Advantages

• Economical to use geothermal energy.
• Does not cause any pollution.

Disadvantages

• Geothermal energy is not available everywhere.
• Deep drilling in the earth to obtain geothermal energy is very difficult and expensive.

4. Nuclear Energy

• The energy released during a nuclear reaction is called nuclear energy.
• It can be obtained by two types of nuclear reactions:

(i) Nuclear fission
(ii) Nuclear fusion

(i) Nuclear Fission:

• ‘Fission’ means split up.
• The process in which the heavy nucleus of a radioactive atom (such as uranium, plutonium
  or thorium) split up into smaller nuclei when bombarded with low energy neutrons, is called nuclear fission.
• A tremendous amount of energy is produced.
• U-235 is used as a fuel in nuclear reactors in the form of uranium rods.

Working: In a nuclear reactor self sustaining chain reaction releases energy at a controlled rate, which is used to produce steam and further generate electricity.

(ii) Nuclear Fusion: When two nuclei of light elements (like hydrogen) combine to form a heavy nucleus (like helium) and tremendous amount of energy is released it is called nuclear fusion.

• Very-very high temperature and pressure is needed for fusion.
• Hydrogen bomb is based on this phenomenon.
• Nuclear fusion is the source of energy in the sun and other stars.

Advantages

• Production of large amount of useful energy from a very small amount of nuclear fuel.
• Does not produce greenhouse gases like C02.

Disadvantages

• Environmental contamination due to improper nuclear waste storage and its disposal.
• Risk of accidental leakage of harmful radiations.
• High cost of installation.
• Limited availability of nuclear fuel.

Environmental Consequences
Exploiting any source of energy disturbs the environment in some way or the other. Thus, the source we would choose depends upon the following factors:

• Ease of extracting energy from the source.
• Cost of extracting energy from the source.
• Efficiency of technology available to extract energy.
• The environmental damage caused by using that source.

On this page, you will find Magnetic Effects of Electric Current Class 10 Notes Science Chapter 13 Pdf free download. CBSE NCERT Class 10 Science Notes Chapter 13 Magnetic Effects of Electric Current will seemingly help them to revise the important concepts in less time.

CBSE Class 10 Science Chapter 13 Notes Magnetic Effects of Electric Current

Magnetic Effects of Electric Current Class 10 Notes Understanding the Lesson

When an electric current is passed through a conductor, a magnetic field is produced around it.

1. Magnetic field

• The region surrounding a magnet, in which the force of the magnet can be detected, is said to have a magnetic field.
• Magnetic field is a quantity that has both direction and magnitude.
• The direction of the magnetic field is taken to be the direction in which a north pole of the compass needle moves inside it.

2. Magnetic field lines

• Magnetic field lines- are the imaginary lines along which the iron filings align themselves.
• By convention, the field lines emerge from the north pole and merge at the south pole. Inside the magnet, the direction of field lines is from the south pole to the north pole.

Properties of Magnetic field line

• Magnetic field lines are closed curves.
• The relative strength of the magnetic field is shown by the degree of closeness of the field lines.
• No two field lines can cross each other as at the point of intersection the compass needle would point towards two directions, which is not possible.

3. Magnetic field due to current carrying conductor

• The magnetic field around a current carrying conductors forms a pattern of concentric circles.
• The magnitude of the magnetic field produced at a given point increases as the current through the wire increases.
• The magnetic field produced by a given current decreases as the distance from it increases.

4. Right-hand thumb rule: The direction of magnetic field produced by a current carrying conductor can be found out by using the right-hand thumb rule.

Imagine that you are holding a current-carrying straight conductor in your right hand such that the thumb points towards the direction of current. Then your fingers will wrap around the conductor in the direction of the field lines of the magnetic field, as shown in Figure. This is known as the right hand thumb rule.

(a) A pattern of concentric circles indicating the field lines of a magnetic field around a straight conducting wire. The arrows in the circles show the direction of the field lines. (b) A close up of the pattern obtained.

5. Magnetic field due to current-carrying circular loop

• At the centre of a current-carrying loop, the magnetic field appears to be a straight in line.
• The magnetic field produced by a current-carrying wire at a given point depends directly on the current passing through it.

6. Magnetic field due to a solenoid
Solenoid: A coil of many circular turns of insulated copper wire wrapped closely in the shape of a cylinder is called a solenoid.

• The pattern of the magnetic field around a current-carrying solenoid is same as that of the bar magnet. One end of the solenoid behaves as a magnetic north pole, while the other behaves as south pole.
• The field lines inside the solenoid are in the form of parallel straight lines.
• The field is uniform inside the solenoid.
• A strong magnetic field produced inside a solenoid can be used to magnetise a piece of magnetic material, like soft iron, when placed inside the coil. The magnet so formed is called an electromagnet.
  

7. Force on a current-carrying conductor in a magnetic field

• A current carrying conductor when placed in a magnetic field experiences a force.
• If the direction of the field and that of the current are mutually perpendicular to each other, then the force acting on the conductor will be perpendicular to both and will be given by Fleming’s left hand rule.
• Fleming’s left-hand rule: According to this rule, stretch the thumb, forefinger and middle finger of your left hand such that they are mutually perpendicular. If the forefinger points in the direction of magnetic field and the middle finger in the direction of current, then the thumb will point in the direction of the force acting on the conductor.

8. Electric motor: An electric motor is a rotating device that converts electrical energy to mechanical energy.
Principle: A current carrying conductor when placed in a magnetic field experiences a force.
Commercial motors are made up of:

• an electromagnet in the place of permanent magnet.
• large number of turns of the conducting wire in the current carrying coil.
• a soft iron core on which the coil is wound.

Electromagnetic induction: The phenomenon of electromagnetic induction is the production of induced current in a coil placed in a region where the magnetic field changes with time.

• The magnetic field may change due to relative motion between the coil and the magnet.
  
• If the coil is placed near a current carrying conductor, the magnetic field may change either due to a change in the current through the conductor or due to the relative motion between the coil and conductor.
• 

Fleming’s right-hand rule to know the direction of the induced current. Stretch the thumb, forefinger and middle finger of the right hand so that they are perpendicular to each other, as shown in the figure. If the forefinger indicates the direction of the magnetic field and the thumb shows the direction of motion of the conductor, then the middle finger will show the direction of induced current. This simple rule is called Fleming’s right-hand rule.

Fleming’s right-hand rule.
A galvanometer is an instrument that can detect the presence of a current in a circuit. The pointer remains at zero (the centre of the scale) for zero current flowing through it. It can deflect either to the left or to the right of the zero mark depending on the direction of current.
The induced current is found to be the highest when the direction of motion of the coil is at right angles to the magnetic field.

Electric Generator: A generator converts mechanical energy into electrical energy.

Principle: It works on the principle of electromagnetic induction.
AC generator produces AC current and DC generator produces DC current.

9. AC and DC

• The difference between the direct and alternating currents is that the direct current always flows in one direction, whereas the alternating current reverses its direction periodically.
• In India, the AC changes direction after every 1/100 second, that is, the frequency of AC is 50 Hz.
• An important advantage of AC over DC is that electric power can be transmitted over long distances without much loss of energy.

10. Domestic Electric circuits

• In our houses we receive AC electric power of 220 V with a frequency of 50 Hz. One of the wires in this supply is with red insulation, called live wire. The other one is of black insulation, which is a neutral wire. The potential difference between the two is 220 V. The third is the earth wire that has green insulation and this is connected to a metallic body deep inside the earth. It is used as a safety measure to ensure that any leakage of current to a metallic body does not give any severe shock to a user.
• Fuse is the most important safety device, used for protecting the circuits due to short-circuiting or overloading of the circuits.

Class 10 Science Chapter 13 Notes Important Terms

Magnetic field: The area around a magnet in which its magnetic force can be experienced.

Right-Hand Thumb Rule: Imagine that you are holding a current carrying straight conductor in your right hand such that the thumb is pointing towards the direction of current. Then the fingers wrapped around the conductor will give the direction of the magnetic field.

Solenoid: A coil of many circular turns of insulated copper wire wrapped closely in a cylindrical form.

Electromagnet: An electomagnet is a type of magnet in which the magnetic field is produced by an electric current. The magnetic field disappears when the current is turned off.

Felming’s Left-Hand Rule: Stretch the thumb, forefinger and middle finger of your left hand such that they are mutually perpendicular. If the forefinger points in the direction of magnetic field, the middle finger in the direction of current then the thumb will point in the direction of motion or force.

Electromagnetic Induction: When a conductor is placed in a changing magnetic field, some current is induced in it. Such current is called induced current and the phenomenon is called electromagnetic induction.

Fleming’s Right-Hand Rule: Hold the thumb, the forefinger and the middle finger of right hand at right angles to each other. If the forefinger is in the direction of magnetic field and the thumb points in the direction of motion of the conductor, then the direction of induced current is indicated by the middle finger.

Electric motor: An electric motor is a rotating device that converts electrical energy to mechanical energy.

Electric generator: A generator converts mechanical energy into electrical energy.

Alternate Current (A.C.): The current which reverses its direction periodically.

Direct Current (D.C.): The current which flows in one direction only.

Earth Wire: Protects us from electric shock in case of leakage of current especially in metallic body appliances. It provides a low resistance path for current in case of leakage of current.

Short Circuit: When live wire comes in direct with neutral wire accidently.

Overloading: When current drawn is more than current carrying capacity of a conductor, it results in overloading.