Q.1 Explain the idea of Satyagraha according to Gandhiji. (2014 D)
Answer:
Mahatma Gandhi returned to India in 1915 from South Africa. Gandhiji’s novel method of mass agitation is know as ‘Satyagraha’. Satyagraha emphasised truth. Gandhiji believed that if the cause is true, if the struggle is against injustice, then physical force was not necessary to fight the oppressor. A satyagrahi can win the battle through non-violence. People, including oppressors, had to be persuaded to see the truth. Truth was bound to ultimately triumph. Gandhiji believed that dharma of non-violence could unite all India.

Q.2
Explain the effects of ‘worldwide economic depression’ on India, towards late 1920s. (2013 OD)
Answer:
In 19th century, colonial India had become an exporter of agricultural goods and an importer of manufactures.
The worldwide economic depression immediately affected Indian trade. India’s exports and imports nearly halved between 1928 and 1934. As international prices crashed, prices in India also plunged. Peasants producing for the world market were worst hit. Though agricultural prices fell, the colonial government refused to reduce revenue demands. Peasants indebtedness increased. For example, Jute producers of Bengal.

In these depression years, India became an exporter of precious metals, notably gold.

Q.3
Explain any three facts about the new economic situation created in India by the First World War. (2011 D)
Answer:
The First World War created a dramatically new economic situation in India:
(i) Manchester imports into India declined as the British mills were busy with war production to meet the needs of the army paving the way for the Indian mills to supply for the huge home market.

(ii) As the war prolonged, Indian factories were called upon to supply war needs. As a result new factories were set up, new workers were employed and everyone was made to work longer hours.

(iii) Cotton production collapsed and exports of cotton cloth from Britain fell dramatically after the war, as it was unable to modernize and compete with US, Germany, Japan. Hence within colonies like India, local industrialists gradually consolidated their position capturing the home market.

Q.4
How did the plantation workers understand the idea of ‘Swaraj’? Explain. (2011 OD)
Answer:
For the plantation workers of Assam, “Swaraj” meant freedom to move freely in and out of the confined space in which they all were enclosed and also to be able to keep the link with their native village intact. Under the Inland Emigration Act of 1859, plantation workers were not allowed to leave their tea gardens without permission, which they were rarely given.

When they heard of the Non-cooperation Movement, thousands of workers defied authorities, left the plantations and headed home.

Q.5
Explain the circumstances under which Gandhiji decided to call off the Civil Disobedience Movement in 1931. (2012 OD)
Answer:
Gandhiji decided to call off the Civil Disobedience movement in 1931 because:

1. Political leaders like Khan Abdul Ghaffar Khan were arrested. More than one lakh people were arrested.
2. Government responded with brutal repression and peaceful satyagrahis were arrested. Women and children were beaten up.
3. It resulted in an uprising in Peshawar in 1930.
4. Industrial workers in Sholapur attacked police post. In Chittagong, the revolutionaries captured the armoury and a pitched battle was fought between the government troops and the revolutionaries. (any three)

In such a situation, Gandhiji called off the movement and the Gandhi-Irwin Pact was signed.

Q.6
Explain the reaction of Indian people against the Rowlatt Act passed through the Imperial Legislative Council in 1919. (2012 OD)
Answer:
Reaction of Indian people against the Rowlatt Act of 1919:

1. Rallies were organized against this Act.
2. Railways, workshops and shops closed down.
3. The procession in Amritsar provoked widespread attacks on buses, post offices, railway stations, telegraphic lines, etc.
4. On 6th April Gandhiji held Hartal against this unjust law (Rowlatt Act).
5. The peaceful demonstration in Jallianwala Bagh led to a violent movement all across the country.

Q.7
How had the First World War created a new economic situation in India? Explain with three examples. (2013 D)
Answer:
The First World War created a dramatically new economic situation in India:
(i) Manchester imports into India declined as the British mills were busy with war production to meet the needs of the army paving the way for the Indian mills to supply for the huge home market.

(ii) As the war prolonged, Indian factories were called upon to supply war needs. As a result new factories were set up, new workers were employed and everyone was made to work longer hours.

Q.8 Explain any three effects of the Non-cooperation Movement on the economy of India. (2011 OD)
Answer:
The economic sphere was affected by the Non-cooperation Movement:

1. Foreign goods were boycotted, liquor shops were picketed and foreign cloth was burnt. The import of foreign cloth halved between 1921-1922. Its value dropped from ₹ 102 crore to ₹ 57 crore.
2. Many merchants and traders refused to trade in foreign goods or finance foreign trade.
3. People began discarding imported clothes and wearing Indian ones.
4. The production of Indian textile mills and handlooms went up. Use of khadi was popularized.

Q.9
How did the rich peasants and women take part in Civil Disobedience Movement? (2011 OD)
Answer:
Role of rich peasants:

1. Being producers of commercial crops, they were hard hit by trade-depression and falling prices.
2. As their cash income reduced, they found it impossible to pay the government’s revenue demand.
3. These rich peasants became ardent supporters of the Civil Disobedience Movement.
4. For them fight for Swaraj was a struggle against high revenues.

Role of women:

1. Women participated in protest marches, manufactured salt and picketed foreign cloth and liquor shops. Many women went to jail.
2. Women who participated in the Civil Disobedience Movement, came from high-caste families in urban areas and rich peasant households in rural areas.

Q.10
Why did Non-cooperation Movement gradually slow down in cities? Explain any three reasons. (2012 D, 2013 OD)
Answer:
The Non-cooperation Movement gradually slowed down in cities for a variety of reasons:

1. Khadi cloth was more expensive than mill cloth and poor people could not afford to buy it. As a result they could not boycott mill cloth for too long.
2. Alternative Indian institutions were not there which could be used in place of the British ones. These were slow to come up.
3. So students and teachers began trickling back to government schools and lawyers joined back work in government courts.

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Q.1 Explain any three beliefs of the conservatism that emerged after 1815. (2011 D)
Answer:
Three beliefs of conservatism that emerged after 1815 were:

1. Established and traditional institutions of state and society like monarchy, the Church, property and family should be preserved.
2. They believed in the modernization of the traditional institution to strengthen them, rather than returning to the society of pre-revolutionary days.
3. Also they believed that abolition of feudalism and serfdom and replacing it with a modern army, an efficient bureaucracy and a dynamic economy could strengthen autocratic monarchies of Europe.

Q.2
Explain the contribution of Otto von Bismarck in German unification. (2011 D)
Answer:
Contribution of Otto von Bismarck in German unification. Nationalist feelings started spreading amongst the middle class Germans, who in 1848, tried to unite different parts of German confederation into a nation state to have an elected parliamentarian government. However, this liberal movement was repressed by the combined forces of monarchy and military supported by Prussian landowners.

Prussian Chief Minister, Otto von Bismarck, took the responsibility of national unification with the help of Prussian army and bureaucracy. Under his leadership he fought three wars over seven years with Austria, Denmark and France. Prussia was victorious in all these wars and the process of unification of Germany was completed as a result of Prussia’s victory over France.

Q.3
Explain any three ways in which nationalist feelings were kept alive in Poland in the 18th and 19th centuries. (2011 OD)
Answer:
The three ways in which nationalist feelings were kept alive in 18th and 19th centuries in Poland:
(i) Emphasis on vernacular language. Language played an important role in developing nationalist sentiments. The use of the Polish language came to be seen as a symbol of struggle against Russian dominance. For example, In Poland, following armed rebellion against Russian rule, Polish was used for church gatherings and religious instruction. As a result, a number of priests and bishops were put in jails or sent to Siberia as punishment for their refusal to preach in Russian.

(ii) Emphasis on collection of local folklore. It was not just to recover an ancient national spirit, but also to carry the modern nationalist message to the large audience who were mostly illiterate.

(iii) Use of music to keep the nationalist feeling alive. For example, Karol Kurpinski, celebrated the national struggle through his operas and music, turning folk dances like the polonaise and mazurka into nationalist symbols.

Q.4
Explain the contribution of Giuseppe Mazzini in spreading revolutionary ideas in Europe. (2011 OD)
Answer:
The year following 1815, was the period of revolutionaries. Most of the revolutionaries were committed to oppose monarchical forms and to fight for liberty and freedom

One such prominent revolutionary was “Giuseppe Mazzini”, an Italian revolutionary. Mazzini also saw the creation of nation-states as a necessary part in the struggle for freedom. Ele strongly believed in the unification of Italy as a single unified republic which could be the basis of Italian liberty.

Mazzini’s relentless opposition to monarchy and his vision of a democratic republic frightened the Conservatives. His ideas also influenced the revolutionaries of Germany, France, Switzerland and Poland. Question 14. Describe any three reforms introduced by Napoleon in the territories he conquered. (2011 D)
Answer:
Three reforms introduced by Napoleon in the territories he conquered were:

1. The Napoleonic Code —It finished all the privileges based on birth and established equality before law and secured the right to property.
2. He simplified administrative divisions, abolished the feudal system and freed peasants from serfdom and manorial dues.
3. He introduced uniform laws, standardized weights and measures and common national currency to facilitate the movement and exchange of goods and capital from one place to another.

Q.5.
Explain any three causes of conflict in the ‘Balkan area’ after 1871. (2011 OD)
Answer:
The nationalist tensions emerged in the Balkans due to the following reasons:
(i) Balkans was a region of geographical and ethnic variation comprising modern-day Romania, Bulgaria, Albania, Greece, Macedonia, Croatia, Bosnia-Herzegovina, Slovenia, Serbia and Montenegro whose inhabitants were known as the Slavs. A large part of Balkans was under the control of the Ottoman empire.

(ii) After the decline of the Ottoman empire and the growth of romantic nationalism in the Balkans, the region became very explosive. Its European subject nationalities broke away from its control and declared independence.

(iii) As the different nationalities struggled to define their identity and independence, the Balkan area became an area of intense conflict. The Balkan states were fiercely jealous of each other and each hoped to gain more territory at the expense of others.

(iv) Balkan also became the scene of big power rivalry. Russia, Germany, England, Austria, Hungry — all big powers were keen in countering the hold of other powers. This ultimately turned Balkan into a war region which eventually provided a minor cause for the First World War.

Q.6 How did the local people in the areas conquered by Napoleon react to French rule? Explain. (2014 D)
Answer:
The reactions of the local population to the French rule were mixed.

Initially, in many places such as Holland and Switzerland, as well as in cities like Brussels, Mainz, Milan and Warsaw, the French armies were welcomed as harbingers of liberty. As new administrative arrangements did not go hand in hand with political freedom, enthusiasm turned into hostility. Increased taxation, censorship, forced conscription into the French armies to conquer the rest of Europe, outweighed the advantages of the administrative changes.

Q 7.
Explain the conditions that were viewed as obstacles to the economic exchange and growth by the new commercial classes during the nineteenth century in Europe. (2014 OD)
Answer:
In the economic sphere, liberalism stood for the freedom of markets and the abolition of state-imposed restrictions on movement of goods and capital.

1. But in the 19th century Napoleon’s administrative measures had created out of countless small principalities a confederation of 39 states. Each possessed its own currency, and weights and measures.
2. A merchant travelling from Hamburg to Nuremberg had to pass through 11 custom barriers and pay 5% duty at each one of them.
3. As each region had its own system of weights and measures this involved time-consuming calculations.

Q.8 Describe the events of French Revolution which had influenced the people belonging to other parts of Europe. (2015 D)
Answer:

• The first clear-cut expression of nationalism came with the French Revolution in 1789. In 1789, France was under the rule of an absolute monarch.
• When the revolutionaries came to power in France, they were determined to create a new sense of unity and nationhood. For this, they emphasized the concept of France being the father land (La Patrie) for all French people, who were from now on addressed as citizens (citoyen). They were given the tri-colour flag, the three colours representing liberty, equality and fraternity.

French revolutionaries introduced various other measures such as:

1. The Estate General was elected by the body of active citizens and renamed the National Assembly.
2. New hymns were composed, oaths taken and martyrs commemorated all in the name of the nation.
3. A centralised administrative system was put in place and it formulated uniform laws for all citizens within its territory.
4. Internal customs, duties and dues were abolished and a uniform system of weights and measures was adopted.
5. Regional dialects were discouraged and French, as it was spoken and written in Paris, became the common language of the nation.

Q 9
How had the female figures become an allegory of the nation during nineteenth century in Europe? Analyse. (2016 D)
Answer:
Artists in the eighteenth and nineteenth centuries portrayed nations 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 in concrete form. That is, the female figure became the allegory of the nation.

In France, she was named Marianne —a popular Christian name and in Germany, Germania. Germania wears a crown of oak leaves as the German oak stands for heroism. The characteristics of Marianne were drawn from those of Liberty and Republic —the red cap, the tricolour and cockade.

Q.10 What did Liberal Nationalism stand for? Explain any four ideas of Liberal Nationalists in the economic sphere. (2011 OD)
Answer:
Liberalism or Liberal Nationalism stood for freedom for the individual and equality of all before the law. Lour ideas of Liberal Nationalists in the economic sphere are:

1. Liberalism stood for freedom of markets and abolition of state imposed restriction. For example, Napoleon’s administration was a confederation of 29 states, each of these possessed its own currencies, weight and measures. Such conditions were viewed as obstacles to economic exchange.
2. Liberal Nationalists argued for the creation of a unified economic territory allowing the unhindered movement of goods, people and capital.
3. In 1834, a customs union or ” zollverein” was formed. The union abolished tariff barriers and reduced the number of currencies from 30 to 2.
4. The creation of a network of railways further stimulated mobility, harnessing economic interest to national unification.

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Q.1 Today the world has become a “global village”. Justify this statement.
Answer:
Today the world has become a “large village” because of:

1. efficient and fast means of transport and
2. development of telecommunication and satellite communication systems.

These two functions, i.e. various means of transport and communication have reduced time and distance, have brought the world closer and the physical distances have become meaningless. For example, now trading from local levels has been extended to the international level and even financial transactions can take place round the world in no time. All this has been made possible because of efficient and quick means of transport and communication.

Q.2 Modern means of transport and communication serve as lifelines of our nation.” Justify this statement by giving supportive arguments.
Or
“Efficient means of transport are prerequisites for the fast development of the country.” Express your views in favour of this statement. (2016 D, 2014 OD)
Answer:
India is well linked with the rest of the world despite its vast size and diversities because of efficient means of transport and communication. They are rightly called the lifelines or arteries of a nation because:

1. Economic development of a country depends on the well developed and efficient means of transport and communication.
2. They are indispensable for movement of people, goods and services from one place to another.
3. They have contributed to socio-economic progress in many ways by connecting far flung areas of the country.
4. They have enriched all aspects of our lives — social, cultural, individual and economic.
5. They promote trade, tourism and business thus adding value to the economy.
6. Transport and communication have made possible international trade which is essential for every economy as no country is self-sufficient in all resources.
7. They link areas of production with consumption, i.e. agricultural farms are linked to the markets and industries.

Q.3 Why do the movement of goods and services form one place to another require fast and efficient means of transport? Explain with examples.
Answer:
Transport plays an important role in the economy. Because of transport raw materials reach the factory and finished products reach to the consumer. The pace of development of a country depends upon the production of goods and services as well as their movement over space. Today the world has converted into a large village with the help of efficient and fast moving transport:

1. Good transport helps in quick carrying of raw materials from remote areas to the production centre and allows distribution of goods efficiently.
2. Transport helps in the development of communication. Various means of communication help us in interacting with other people in all the parts of the world. It has brought the world closer.
3. Transport like railways helps us in conducting various activities like business, sight seeing, pilgrimages, etc.

Q.4 How are means of transport and communication complementary to each other? Explain with three examples. (2013 OD)
Answer:

1. Transport and communication establish links between producing centres and consuming centres. Trade or the exchange of such commodities relies on transportation and communication. Transport provides the network of links and carriers through which trade takes place.
2. Dense network of roads, railways and airways connect the remote areas of the country hence help in production and distribution of goods and services.
3. Advancement in communication system has accelerated trade by carrying information all over the world quickly.

Q.5 Why is road transport more useful than rail transport in India. Give reasons. (2016 OD, 2013 D)
Or, “Roadways still have an edge over railways in India”. Give reasons.
Answer:
Roadways score over railways:

1. Construction of roads is easier and cheaper as compared to railways.
2. Roads provide door to door service, thus the cost of loading and unloading is much lower as compared to railways which generally leave the people and goods at the destined railway stations.
3. Roads can negotiate higher gradients of slope and, as such, can traverse through mountainous terrain. But railways cannot negotiate steep gradients.
4. Road transport is economical in transportation of few persons and relatively smaller amount of goods over short distances.
5. Road transport is also used as a feeder to other modes of transport. They provide links between railway stations, airports and sea ports.
6. They link agricultural farms with markets and industries, thus linking rural and urban areas.

Q.6 Analyse the physiographic and economic factors that have influenced the distribution pattern of the railway network in our country. (2015 D)
Or, ‘The distribution pattern of Indian Railway network is influenced by the physiographic factors. Examine the statement. (2013 OD)
Answer:
Factors that affect the distribution pattern of railway network in India:
(i) Physiographic factors. The Northern plains with vast level land, high population density and rich agricultural resources provide most favourable conditions for railway network. The nature of terrain and the number of rivers running through the region determine the density of railway network in that region. Mountains, marshy, sandy and forested areas have sparse network whereas plain areas have dense network of the railways. It was difficult to lay railway lines on the sandy plains of Western Rajasthan, swamps of Gujarat and forested tracks of Madhya Pradesh.

(ii) Economic factors. Regions which have rich resources and are economically more developed have denser network of railways in comparison to the regions with low economic development.

(iii) Administrative factors. The administrative and political decisions also affect the distribution of railway network in a region.

Q.7 List four factors which favoured the development of dense network of railways in the northern plains. (2012 OD)
Answer:
Four reasons for dense network of railways in northern plains are:

1. The vast level land provided the most favourable conditions for their growth. It is cheaper and easier to construct railway tracks here.
2. The agricultural and industrial development in this region necessitated the development of railway lines.
3. High population density in this region further required the development of railway lines.
4. Resources such as iron and steel, fuels, etc., required for the development of railways are available in abundance in the northern plains.

Q.8 Write four merits of air travel. Also mention any two demerits of air transport. (2012 OD, 2011 D)
Answer:
Merits of air travel.

1. Air travel is the fastest, most comfortable and prestigious mode of transport.
2. India is a vast country with wide variation in relief. Air transport can cover difficult terrains like high mountains of the Himalayas, the Western Ghats, dreary deserts of Rajasthan, dense forests and long coastlines with great ease.
3. Air travel has made access easier in the north-eastern part of the country, which is marked with the presence of big rivers like Brahmaputra, dissected relief, dense forests, frequent floods and international frontiers.
4. At the time of natural calamities, relief measure and relief operations can be carried out quickly with the help of air transport.
5. High value perishable goods can easily be exported or imported by airways.

Demerits of air transport.

• Air travel is very expensive and not within the reach of the common people. Air travel is very luxurious.
• It is adversely affected by bad weather conditions.

Q.9 Why is ‘tourism’ considered as a trade and industry in India? Give reasons in support of your answer. (2015 OD, 2014 D)
Answer:

1. With increase in the number of foreign tourists visiting India, we earned foreign exchange worth Rs. 21,828 crore in 2004 which is further increasing year by year making tourism an important trade.
2. Over 2.6 million foreign tourists visit India every year for appreciating our heritage, our culture for medical purposes or for business purposes, etc.
3. Over 15 million people are directly engaged in the tourism industry.
4. Tourism promotes national integration, provides support to local handicrafts and cultural pursuits.
5. Tourism also helps in the development of international understanding about our culture and heritage.
6. Rajasthan, Goa, Jammu & Kashmir and temple towns of south India are the most popular tourist destinations. These states earn huge sums of money from tourism trade.

Q.10 Give reasons for which foreign tourists visit India. (2014 D)
Answer:
Foreigners visit India for various purposes. These are:

1. Heritage tourism
2. Eco-tourism
3. Adventure tourism
4. Cultural tourism
5. Medical tourism
6. Business tourism
   • Broadened cultural awareness of each others tradition.
   • It is economically viable. India is a great value destination as tourists can travel cheaply and lavishly.
   • Indian hospitality is famous worldwide — ‘Atithi devo bhava’.
   • India is an avenue to explore spirituality through yoga, meditation.
   • Indian cuisine predominantly, North Indian is world famous.
   • India has several historical and architectural attractions. Regional handicrafts and ethnic designs of traditional products attract tourists.

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Q.1 Write the importance of ‘manufacturing sector’ for our nation.
Or, “Manufacturing industry is considered the backbone of economic development of India.” Give reasons. (2015 OD, 2011 D)
Answer:
Importance of manufacturing industries for India:

1. It helps in modernizing agriculture, which is the base of our economy.
2. It reduces heavy dependence on agricultural income by providing jobs in non-agricultural sectors.
3. Industrial development is necessary for eradication of poverty and unemployment because people get jobs and generate more income.
4. Export of manufactured goods expands trade and brings in much needed foreign exchange.
5. Industries bring riches faster to a nation because manufacturing changes raw materials into finished goods of a higher value, so industrial development brings prosperity to the country.

Q.2 List the major factors which affect the location of an industry at a place. What is the key to the decision of ‘factory location’? (2011 D, 2011 OD, 2015 D)
Answer:

1. Raw material. Cheap and abundant availability of raw material. Industries which use heavy and perishable raw material have to be located close to the source of raw material.
2. Labour. Availability of cheap labour is necessary for keeping the cost of production low.
3. Power. Cheap and continuous supply of power is extremely necessary for continuity in the production process.
4. Capital. It is necessary for developing infrastructure, for the entire manufacturing process and for meeting manufacturing expenditure.
5. Banking and insurance facilities, favourable government policies are other factors which affect location of an industry.
   The ‘key’ to the decision of a factory location is least cost so that the venture is profitable.

Q.3 classify industries on the basis of capital investment. How are they different from one another? Explain with examples. (2016 D)
Answer:
On the basis of capital investment industries can be classified as:

• Small-scale industry
• Large-scale industry

Difference:
If the investment is more than one crore rupees in any industry, it is considered as a large scale industry.
For example, Iron and Steel industry, Cement industry.
If the investment is less than one crore rupees in any industry, it is considered as a small scale industry.
For example, Plastic industry, Toy industry.

Q.4 Classify industries on the basis of source of raw material. How are they different from each other? (2016 OD)
Answer:
On the basis of sources of raw material industries are classified as:
(i) Agro based industries;
(ii) Mineral based industries
Difference between Agro-based industries and Mineral-based industries

Q.5 Explain the significance of textile industry in India. (2011 D)
Or
The textile industry is the only industry which is self reliant and complete in the value-chain? Justify this statement? (2016 D)
Or
“Textile industry occupies a unique position in the Indian economy”. Support the statement with appropriate arguments. (2015 D)
The Textile industry occupies a unique position in the Indian Economy because:

1. It contributes significantly to industrial production (14%).
2. It employs largest number of people after agriculture, i.e. 35 million persons directly.
3. Its share in the foreign exchange earnings is significant at about 24.6%.
4. It contributes 4% towards GDP.
5. It is the only industry in the country which is self-reliant and complete in the value chain, i.e., from raw material to the highest value added products.

Q.6 List factors which favoured the location and concentration of cotton textile industry in Maharashtra
and Gujarat in early years. (2012 D, 2015 OD)
Answer:

1. Availability of raw cotton was abundant and cheap because these are the traditional cotton growing States.
2. Moist climate in these coastal States also helped in the development of cotton textile industry because humid conditions are required for weaving the cloth, else the yarn breaks.
3. Well developed transportation system and accessible port facilities in Maharashtra and Gujarat led to their concentration there.
4. Proximity to the market is yet another factor as cotton clothes are ideal and comfortable to wear in these warm and humid States.
5. Cheap labour was abundantly available.

Q.7 Electronic industry has revolutionized the life of the masses and the country’s economy.” Justify the statement with suitable arguments.
Answer:
Electronic industry has revolutionized the life of the people and the country’s economy because:

1. It produces a wide range of products from transistor sets to televisions and computers for the masses.
2. It has helped us set up telephone exchanges, telephones, cellular telecom, radios and many other equipments which have application in space technology, aviation, defence, meteorological departments, etc.
3. It has generated employment for a large number of people. It employed over one million people by March 2005, out of these 30% are women employees.
4. This industry has been a major foreign exchange earner because of its fast growing Business Process Outsourcing (BPO) Sector.
5. India is one of the leading countries in software development. We have 18 software technology parks which provide high data communication facility to software experts.

Q.8 Suggest measures to control water pollution caused by industries. (2013 D)
Answer:

1. Minimising the use of water for processing by reusing and recycling it in two or more successive stages.
2. Harvesting of rain-water to meet water requirements of industries and other domestic purposes.
3. Treating hot water and effluents before releasing them in rivers and ponds in the following ways:
   • Primary treatment by mechanical means such as screening, grinding, flocculation and sedimentation.
   • Secondary treatment by biological process.
   • Tertiary treatment by biological, chemical and physical processes. This involves recycling of waste water.

Q.9 Explain the pro-active approach adopted by the National Thermal Power Corporation (NTPC) for preserving the natural environment and resources? (2011 OD, 2015 OD)
Answer:
NTPC is taking the following measures in places where it is setting up power plants:

1. Optimum utilisation of equipment by adopting latest techniques and upgrading existing equipment.
2. Minimising waste generation by maximising ash utilisation.
3. Providing green belts for nurturing ecological balance.
4. Reducing environmental pollution through ash pond management, ash water recycling system and liquid waste management.
5. Ecological monitoring, reviews and online data base management for all its power stations.

Q.10 Suggest any three steps to minimise the environmental degradation caused by the industrial development in India. (2016 OD)
Answer:
Steps to minimize the environmental degradation caused by industrial development in India are:

1. Minimizing use of water for processing by reusing and recycling in two or more successive stages. Harvesting of rain water to meet water requirements of industries and other domestic purposes.
2. Treating hot water and effluents before releasing them in rivers and ponds.
3. Particulate matter in the air can be reduced by fitting smoke to factories with electrostatic precipitators, fabric filters, scrubbers and inertial separators. Smoke can be reduced by using oil or gas instead of coal in factories.
4. Machinery and equipments can be fitted with silencers to prevent noise pollution.

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Q.1 What factors does primitive subsistence farming depend on?
Answer:
Factors:

• Monsoons
• Natural fertility of the soil
• Suitability of other environmental conditions to the crops grown.

Q.2
Write main characteristics of ‘slash and burn’ agriculture.
Or, Write main characteristics of Primitive Subsistence Farming.
Answer:

• This type of farming is practised in few pockets of India on small patches of land using primitive tools and family/community labour.
• Farmers clear a patch of land and produce cereals and other food crops to sustain their families.
• When the soil fertility decreases, the farmers shift and clear a fresh patch of land for cultivation. This type of shifting allows nature to replenish the fertility of the soil through natural processes.
• Land productivity is low as the farmer does not use fertilisers or other modem inputs.

Q.3Compare ‘intensive subsistence farming’ with that of ‘commercial farming’ practiced in India.
Answer:

Q.4 What are the major differences between primitive subsistence farming and commercial farming? (2013)
Answer:

Q.5 Mention two geographical conditions required for the growth of Maize crop in India. Describe three factors which have contributed to increase maize production. Write four major maize producing states. (2012)
Answer:
Geographical conditions required for the growth of maize crop in .India:

1. It is a kharif crop which requires temperature between 21° C to 27° C. It requires moderate rainfall between 50-100 cm.
2. It grows well in old alluvial soils.
   Maize is a crop which is used both as food and fodder. In some states like Bihar, maize is grown in rabi season also. Maize production in India has increased due to factors like:
   • use of modern inputs such as HYV seeds;
   • use of fertilisers; and
   • use of irrigation facilities.
   • major maize producing state: Karnataka, Uttar Pradesh, Bihar, Andhra Pradesh and Madhya Pradesh.

Q.6 (a) Name three pulses each of Rabi and Kharif season. Write their importance for human beings and for agriculture.
(b) What is India’s position in the world with regard to the production of pulses? Name five leading states producing pulses. (2015)
Answer:
(a) Pulses of Rabi season: Tur (arhar), urad, moong.
Pulses of Kharif season: Masur, peas, gram.
Importance of pulses:

• For agriculture. Being leguminous crops, they help in restoring soil fertility by utilising nitrogen from the air (nitrogen fixation). Therefore, these are mostly grown in rotation with other crops.
• They need less moisture and survive even in dry conditions.

(b) India is the largest producer of pulses in the world.
Major pulse producing states are: Madhya Pradesh, Uttar Pradesh, Rajasthan, Maharashtra and Karnataka.

Q.7 What is India’s position in the world regarding tea production? Name three states each which produce tea in:
(i) North-Eastern India
(ii) Himalayan states/parts of the states
(iii) Peninsular States.
Answer:
India is the leading producer and exporter of tea in the world.
Three states producing tea in each of the following:

Q.8 What are ‘Institutional Reforms’? Enlist various institutional reforms taken by the Indian Government to bring about improvements in agriculture. (2015)
Answer:
Institutional reforms:
Steps taken by the government to bring about improvements in agriculture are termed as ‘Institutional Reforms’.
Some steps are:

1. Collectivisation and consolidation of land holdings to make them economically viable.
2. The green revolution based on the use of package technology and the White Revolution to increase milk production are important strategies which were initiated to improve agriculture.
3. Cooperation with farmers and Abolition of Zamindari system.
4. Provision of crop insurance to protect the farmers against losses caused by natural calamities, i.e. drought, flood, cyclone, fire and disease.
5. Establishment of ‘Grameen Banks’, Cooperative Societies and Banks for providing loan facilities to the farmers at lower rates of interest.
6. Kissan Credit Card (KCC), Personal Accident Insurance Scheme (PAIS) are some other schemes introduced by the government for the benefit of farmers.
7. Special weather bulletins and agricultural programmes for farmers were introduced on the Radio and TV.
8. Announcement of minimum support price, remunerative and procurement prices for crops to check the exploitation of farmers by speculators and middlemen and removing the elements of uncertainty.

Q.9 Define each of the following:
(a) Green Revolution
(b) White Revolution
(c) Yellow Revolution
(d) Blue Revolution
(e) Gene Revolution.
Answer:
(a) Green Revolution. Agricultural Revolution which resulted in increased production of foodgrains because of the use of HYV (High Yielding Varieties) seeds, fertilizers, proper irrigation and other modem inputs.
(b) White Revolution. Revolutionary increase in the production of milk which was spearheaded by Operation Flood.
(c) Yellow Revolution. Increase in the output of oilseeds is termed as Yellow Revolution.
(d) Blue Revolution refers to increased output of fish and fish products.
(e) Gene Revolution refers to the development of genetically modified seeds for increasing the yield per hectare. These seeds are environmentally sustainable.

Q.10 What are coarse grains? Why are they important in India? Name the crops which are included in this category and name three leading states producing each of these crops.
Answer:
Millets are called coarse grains. They are important because they have high nutritional value and make an important part of the diet for poor people.
Most important millets are as follows:

1. Ragi —Leading producer is Karnataka, followed by Tamil Nadu. Himachal Pradesh, Jharkhand, Uttaranchal, Sikkim etc are other important regions.
2. Jowar—Maharashtra is the leading producer followed by Karnataka, Andhra Pradesh, Madhya Pradesh.
3. Bajra—It grows well on sandy soils and shallow black soils. Rajasthan is the largest producer followed by Uttar Pradesh, Maharashtra, Gujarat and Haryana.

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Q.1 Mention any three characteristics of ferrous group of minerals found in India.(2011 D)
Answer:
Metallic minerals that have iron in them are called ferrous minerals. For example, iron ore, manganese, nickel, cobalt etc.
Three characteristics of ferrous group of minerals found in India are:

1. Ferrous minerals account for about three fourths of the total value of the production of metallic minerals.
2. They provide a strong base for the development of metallurgical industries.
3. India exports substantial quantities of ferrous minerals to Japan and South Korea after meeting her internal demands.

Q.2 Why is there a pressing need to use non-conventional sources of energy in India? Explain any three reasons. (2011 D)
Answer:

1. The growing consumption of energy has resulted in India becoming increasingly dependent on fossil fuels such as coal, oil and gas which are found in limited quantity on the earth.
2. Rising prices of oil and gas and their potential shortages have raised uncertainties about the security of energy supply in future, which in turn has serious repercussions on the growth of the national economy.
3. Increasing use of fossil fuels also causes serious environmental degradation like air pollution, water pollution etc.
   So there is an urgent need to use sustainable energy resources like solar, water, wind, tide biomass etc.

Q.3 Make a distinction between hydroelectricity and thermal electricity stating three points of distinction.
Or
What are the two main ways of generating electricity? How are they different from each other. Explain. (2011 OD, 2014 OD)
Answer:
Electricity is generated mainly in two ways:

1. By running water which drives hydro turbines to generate hydro electricity.
2. By burning other fuels such as coal, petroleum and natural gas to drive turbines to produce thermal power.

Q.4 Differentiate between ferrous and non-ferrous minerals with examples. (2013 D)
Answer:
Ferrous minerals:

1. Ferrous minerals account for about three fourths of the total value of the production of metallic minerals.
2. They provide a strong base for the development of metallurgical industries.
3. India exports substantial quantities of ferrous minerals to Japan and South Korea after meeting her internal demands.

Non-ferrous minerals:

1. India’s reserves and production of non-ferrous minerals is not very satisfactory.
2. Non-ferrous minerals include copper, bauxite, lead, zinc and gold.
3. They provide a strong base for the development of metallurgical, engineering and electrical industries.
4. Non-ferrous minerals like copper and bauxite are mainly found in Madhya Pradesh and Odisha respectively.

Q.5 Environmental degradation has been seen everywhere/ Explain any three values that can help to prevent environment degradation. (2014 D)
Answer:
Three values that can help to prevent Environmental Degradation:

1. We must ensure sustainable and equitable use of resources without degrading the environment or risking health or safety.
2. We must raise awareness and consciousness among people about the importance of judicious use of resources to prevent degradation of land, water, vegetation and air.
3. The following measures must be adopted to prevent environmental degradation:
   • Minimising use of water for processing by reusing and recycling it.
   • Smoke can be reduced by using oil or gas instead of coal in factories.
   • Almost all machinery can be redesigned to increase energy efficiency and reduce noise.

Q.6 Which is the most abundantly available fossil fuel in India? Mention its different forms. (2015 OD, 2014 OD, 2008)
Answer:
The most abundantly available fossil fuel is Coal.
There are four types of coal:

1. Anthracite. It is the highest quality hard coal. It contains more than 80% carbon content. It gives less smoke.
2. Bituminous. It is the most popular coal in commercial use and has 60-80% carbon content. Metallurgical coal is high grade bituminous coal and is of special value for smelting iron in blast furnaces.
3. Lignite. It is a low grade brown coal. It is soft with high moisture content.
4. Peat. It has a low carbon and high moisture content. It has low heating capacity and gives lot of smoke on burning.

Q.7 How can solar energy solve the energy problem to some extent in India? Give your opinion. (2015 OD)
Or
Why does solar energy have a bright future in India?
Answer:
Reasons:

1. India is a tropical country and gets abundant sunshine.
2. It has enormous possibilities of tapping solar energy.
3. It is an inexhaustible source of energy which is freely available in nature.
4. It is a cheaper source of energy and is fast becoming popular in rural and remote areas.
5. Photovaltic technology is available which converts sunlight directly into electricity.
6. Because of its abundant and free availability in all parts of India in addition to its ecofriendly nature, solar energy is called the energy of future.

Also use of solar energy will minimise the dependence of rural households on firewood. It will contribute to environmental conservation and reduce pressure on conventional sources of energy.

Q.8 Consumption of energy in all forms has been rising all over the country. There is an urgent need to develop a sustainable path of energy development and energy saving/ Suggest and explain any three measures to solve this burning problem. (2016 OD)
Answer:
Every sector of the national economy—agriculture, industry, transport, (commercial and domestic), needs greater inputs of energy.

With increasing population and changing lifestyles energy consumption is increasing very fast. We are not self sufficient in energy according to demands. Therefore we have to adopt a cautious approach for the judicious use of our limited resources. Conservation of energy should be done at all levels.
Three measures to reduce consumption of energy in all forms:

1. We can do our bit by using public transport systems instead of individual vehicles.
2. Switching off electricity when not in use.
3. Using power saving devices or using non-conventional sources of energy such as solar energy, wind energy etc.
4. Checking the power equipments regularly can help in saving of energy.

Q.9 What are the main types of formations in which minerals occur?
Answer:
Minerals generally occur in the following forms:

1. Veins and lodes. In igneous and metamorphic rocks minerals may occur in the cracks, faults or joints by getting solidified in them. The smaller occurrences are called veins and the larger lodes, eg., metallic minerals like tin, copper, zinc and lead etc. are found in lodes and veins.
2. In sedimentary rocks minerals occur in beds or layers. They are formed as a result of deposition, accumulation and concentration in horizontal strata. Some sedimentary minerals are formed as a result of evaporation, especially in arid regions eg., gypsum, potash and salt.
3. Another mode of formation involves decomposition of surface rocks and the removal of soluble contents, leaving a residual mass of weathered material containing ores. Bauxite is formed this way.
4. Placer deposits. Certain minerals occur as alluvial deposits in sands of valley floors and the base of hills, eg., gold, silver, tin and platinum. These are called placer deposits and contain minerals which are not corroded by water.
5. Ocean waters contain vast quantities of minerals, eg., common salt, magnesium and bromide are largely derived from the ocean waters. The ocean beds are rich in manganese nodules.

Q.10 Distinguish between conventional and non-conventional sources of energy. (2013 D)
Or
Classify energy resources into two categories. Give two examples of each. (2014 OD)
Answer:
Energy sources can be classified as conventional and non-conventional sources.

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Q.1 Explain how water becomes a renewable resource?
Answer:

• Fresh water is mainly obtained from surface run off and ground water. This is continually being renewed and recharged through the hydrological cycle.
• All the water moves within the hydrological cycle making water a renewable resource.

Q.2 What were the different types of hydraulic structures constructed in Ancient India? Give examples.
Answer:
The different types of hydraulic structures were:

• Dams built of stone rubble e.g., during Chandragupta Maurya’s time, dams, lakes and irrigation systems were extensively built.
• Reservoirs or lakes like the Bhopal lake of the 11th century which was one of the largest artificial lakes of its time.
• Embankments and canals for irrigation. Sophisticated irrigation works have been found in Kalinga (Orissa), Kolhapur (Maharashtra), Nagarjunakonda (Andhra Pradesh) etc.
• Many tanks were built to store rainwater e.g., the tank in Huaz Khas in Delhi was built in 14th century to supply water to Siri Fort area.

Q.3 Describe the traditional method of rainwater harvesting adopted in different parts of India.
Answer:
In ancient India, people developed wide-ranging techniques to harvest rainwater.

1. In mountainous areas ‘Guls’ and ‘Kuls’ the diversion channels were built for agriculture.
2. ‘Rooftop rainwater harvesting’ was commonly practised to store drinking water, especially in Rajasthan.
3. Inundation channels for irrigation were developed in the flood plains of West Bengal.
4. In arid and semi-arid regions, agricultural fields were converted into rainfed storage structures, eg. ‘Khadins’ in Jaisalmer and ‘Johads’ in other parts of Rajasthan.
5. In semi-arid and arid regions of Rajasthan, particularly in Bikaner, Phalodi and Barmer, all the houses had underground tanks or ‘tankas’ built inside the house for storing drinking water. They were a part of the well-developed rooftop rainwater harvesting system.

Q.4 What is water scarcity? Write the main reasons for water scarcity. (2015)
Answer:
Water scarcity means shortage of water. It is usually associated with regions having low rainfall or drought prone areas. There are many other reasons which lead to scarcity of water.
These are:

1. Large growing population—means more water required for domestic use and also to produce more food.
2. In the agricultural sector, water resources are being over-exploited to expand irrigated areas and dry-season agriculture.
3. More water required for irrigation purposes to facilitate higher food production, i.e., for doing multiple cropping and for HYV seeds.
4. There is greater demand for water with growing urbanisation and industrialisation.
5. An unequal access to water among different social groups.
6. The quality of water is deteriorating, i.e., getting polluted by domestic and industrial wastes, chemical fertilizers and pesticides used in agriculture.
7. Excessive use of water by industries which also require water to generate hydro-electric power to run them.
8. Over exploitation of water in the urban areas. Housing societies and colonies have their own ground-water pumping devices. This causes depletion of fragile water resources in the cities.

Q.5 Write the adverse effects of over-exploitation of ground water resources.
Answer:

1. Pumping out more water from under the ground may lead to falling ground water levels.
2. It will adversely affect water availability.
3. This, in turn, will affect our agriculture and food security of the people.
4. Impoverishment of water resources may adversely affect the ecological cycle.

Q6 .
Write the main causes of water pollution.
Answer:
Water gets polluted by:

1. Domestic wastes, especially urban sewers.
2. Industrial wastes are disposed off in the water without proper treatment.
3. Chemical effluents from industries and from agricultural sector.
4. Pesticides and fertilisers used in agriculture may get washed into rivers by rain-water and may pollute the water by enriching it with minerals.
5. Many human activities, e.g., religious rituals and immersing of idols, etc. in the water also pollute water.

Q.7 How was water conserved in ancient India? Give any four examples in support of your answer. (2012)
Answer:
Archaeological and historical records show that from ancient times India has been constructing sophisticated hydraulic structures like dams, reservoirs, embankments and canals for irrigation.

1. For example, in the first century B.C., Allahabad had sophisticated water harvesting system channelling the flood water of the river Ganga.
2. During the time of Chandragupta Maurya, dams, lakes and irrigation systems were extensively built.
3. Sophisticated irrigation works have been found in Kalinga in Odisha, Nagarjunakonda in Andhra Pradesh, Bennur in Karnataka and Kolhapur in Maharashtra.
4. Bhopal lake, built in the 11th century, was one of the largest artificial lakes of its time.
5. In the 14th century, Iltutmish constructed a tank in Hauz Khas, Delhi for supplying water in Siri Fort area.

Q.8 What is the main difference between traditional dams and modern dams?
Answer:
Traditionally dams were built to impound rivers and rainwater that could be used later to irrigate the agricultural fields.

Today, dams are referred to as multipurpose projects where many uses of the impounded water are integrated with one another. The main purposes served by these projects are irrigation, electricity generation, flood control, water supply for domestic and industrial use, fish breeding and tourism

Q.9 What are the social consequences of multipurpose projects?
Or
Multipurpose projects have transformed the social landscapes. Explain.
Answer:

1. Local people, especially the landless people, did not gain from these projects.
2. It led to displacement of people which deprived the people of their land and livelihood.
3. It has increased the social gap between the richer landowners and the landless poor.
4. Dams created conflicts between people wanting different uses and benefits from the same water resources.
5. Inter-state water disputes are also becoming common with regard to sharing the costs and benefits of the multipurpose projects.

Q.10 Explain how rooftop rainwater harvesting in semi-arid regions of Rajasthan is carried out. (2012)
Or
Write the features of the ’tankas’ built in the houses of Bikaner, Phalodi and Barmer.
Answer:
‘Rooftop rainwater harvesting’ was commonly practiced to store drinking water, especially in semi-arid and arid regions like Bikaner, Phalodi and Barmer in Rajasthan.

1. In semi-arid and arid regions, all the houses had underground tankas or ‘tankas’ for storing drinking water built inside the house. They were the part of the well-developed rooftop rainwater harvesting system.
2. The tankas could be as large as a big room. One household in Phalodi had a tank that was 6.1 metres deep, 4.27 metres long and 2.44 metres wide.
3. The tankas were built inside the main house or the courtyard.
4. The tanks were connected to the sloping roofs of the houses through a pipe. The falling rain would travel down the pipes and get stored in the underground ‘tankas’. The first spell of rain would not be collected as it cleaned the roof and pipes. The rainwater from subsequent showers was collected.
5. Many houses constructed underground rooms adjoining the tanka to beat the summer heat as it would keep the room cool.

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 Q.1 “Forests play a key role in the ecological system.” Highlight the value of forests in our life.

Answer

• Forests play a key role in the ecological system as these are the primary producers on which all other living beings depend.
• It supports diverse flora and fauna which are part of our life.
• It provide us fruits, flowers, medicine, wood etc.

Q.2 What is biological diversity? Why biodiversity is important for human lives?

Answer

Biological diversity means the variety of all living things, plants, animals and microorganisms living on the earth that are dependent on one other.
It is important for human lives because:
• Human beings depend on biodiversity for their very survival.
• The plants, animals and micro-organisms re-create the quality of air, water and soil which human use for their survival.

Q.3. Distinguish between endangered species and extinct species of wild animals. Give one example of each.

Answer

Endangered species:
• These are species which are in danger of extinction.
• The survival of such species is difficult if the negative factors that have led to a decline in their population continue to operate.
• Examples are black buck, crocodile, Indian wild ass, Indian rhino
Extinct:
• These are species which are not found after searches of known or likely areas where they may occur.
• A species may be extinct from a local area, region, country, continent or the entire earth. As, these species are finished, so they cannot be revived.
• Example – Asiatic cheetah, Pink-head duck.

Q4 Describe the role of the community in forest and wildlife conservation.

Answer

• In Sariska Tiger Reserve, Rajasthan, villagers have fought against mining and destruction of forest by citing the Wildlife Protection Act.
• The inhabitants of five villages in the Alwar district of Rajasthan have declared 1,200 hectares of forest as the Bhairodev Dakav ‘Sonchuri’, declaring their own set of rules and regulations which do not allow hunting, and are protecting the wildlife against any outside encroachments.
• The Bishnois of Rajasthan are well known for protecting black bucks (chinkara) an endangered species, and herds of black buck, nilgai and peacocks can be seen as an integral part of the community and nobody harms them.
• The famous Chipko Movement in the Himalayas led by local communities, especially women, successfully resisted deforestation in several areas.
• Joint forest management (JFM) is a programme which involves local communities in the management and restoration of degraded forests.

Q.5 What are the steps taken by Government to conserve flora and fauna of the country?

Answer

• To protect flora and fauna, the Indian wildlife protection Act was implemented in 1972, with various provisions for protecting habitats.
• An all–India list of protected species was also published. The main aim of the program was towards protecting the remaining population of certain endangered species by banning hunting, giving legal protection to their habitats and restricting trade in wildlife.
• Central and many stage governments established national parks and wildlife sanctuaries.
• The central government announced several projects for protecting specific animals, which were gravely threatened, including the tiger, the one horned rhinoceros, the Kashmir stag etc.
• Most recently, the Indian elephant, black buck, the great Indian bustard and the snow leopard, etc. have been full or partial legal protection against hunting and trade throughout India.

Q.6 Write four major reasons for the depletion of forest cover.
Answer:

1. Deforestation for agricultural purposes.
2. Shifting cultivation which is still practised in substantial parts of tribal belts.
3. Large-scale development of river valley projects.
4. Mining activities have also resulted in deforestation. For example, the tiger reserve in West Bengal is seriously threatened by the ongoing dolomite mining.
5. Environmental pollution and forest fires have also led to depletion of forests.

Q.7 Write three adverse impacts of dolomite mining in the Buxar Tiger Reserve on the ecosystem.
Answer:
Adverse effects of dolomite mining in the Buxar Tiger Reserve:

1. It has caused ecological damage.
2. It has blocked the migration route of several species.
3. It has disturbed the natural habitat of many species.

Q.8 What are ‘Permanent Forest Estates’ and why? Which state has maximum forest cover falling under this category? Write its percentage share in the total forest area of this state.
Answer:
Reserved and protected forests are referred to as the Permanent Forest Estates maintained for the purpose of producing timber and other forest produce.
Madhya Pradesh has the largest area under permanent forests, constituting 75% of its total forest area.

Q.9 Write the major differences between reserved and protected forests.
Answer:
Difference between Reserved and Protected forests

Q.10 33% of area should be under forests’. Justify the statement highlighting the environmental values of forests.
Answer:
Forest area in the country is far lower than the desired 33% of geographical area, as outlined in the National Forest Policy (1952). Forests are considered essential for maintenance of the ecological balance. The livelihood of millions of people who live on the fringes of these forests depend upon it.

Forests play a key role in the ecological system as these are also the primary producers on which all other living beings depend. The forest preserves the ecological diversity and our life support systems—water, air and soil. It also preserves the genetic diversity of plants and animals for better growth of species and breeding. The destruction of forests have marginalised and impoverished many indigenous forest dependent communities. The indirect impact of degradation is severe drought or induced floods. Poverty is a direct outcome of environmental destruction.

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 Q.1“Damage to the ozone layer is a cause for concern.” Justify this statement. Suggest any two steps to limit this damage. ‘ [Delhi]
Answer. Ozone layer prevents the harmful ultraviolet radiation to enter the atmosphere and reach the earth’s surface. Depletion of ozone layer has become a cause for concern because it can cause serious effects on human body and other organisms of the environment like fatal diseases such as skin cancer, changes in genetic material DNA, eye damage, etc.
Two steps to limit this damage are as follows:

1. Judicious use of aerosol spray propellants such as fluorocarbon and chlorofluorocarbons which cause depletion or hole in ozone layer.
2.  Control over large scale nuclear explosions and limited use of supersonic planes.

Q.2  Explain the phenomenon of “biological magnification” How does it affect organisms belonging to different trophic levels particularly the tertiary consumers? [Delhi]
Answer. The process in which harmful chemicals enter a food chain and get accumulated progressively at each trophic level is called biological magnification.
Harmful and toxic chemicals enter our bodies when they are added to soil and water. Use of pesticides to protect the food crops from diseases and pests and chemical wastes of factories are dumped in open or disposed off into rivers. These chemicals are washed down into the soil and ultimately to water table or get absorbed or taken up from the soil by the plants along with water and minerals and in this way harmful chemicals enter the food chain. The quantity of these harmful chemicals increase with increase in trophic level of the food chain because these substances are not degradable. Man is at the top of the food chain, so concentration is maximum in human beings.
Thus, accumulation of DDT has been maximum in man as DDT is used to destroy pests. DDT is accumulated in the following way in this food chain:
This is the reason why our food grains such as wheat and rice, vegetables and fruits and even meat contain varying amounts of pesticides residues. So, the highest trophic level at the extreme right of food chain has the maximum concentration of harmful chemicals in a food chain.

Q.3 (a) What is ‘environmental pollution’?
(b) Distinguish between biodegradable and non-biodegradable pollutants.
(c) Choose the biodegradable pollutants from the list given below:
Sewage, DDT, radioactive waste, agricultural waste. [Delhi]
Answer. (a) Environmental pollution is an undesirable change in the physical, chemical or biological
characteristics of the natural environment, brought about by man’s activities. This pollution may affect the soil, rivers, seas or the atmosphere.

(c) Biodegradable pollutants are sewage and agricultural waste.

Q4 Which of the following groups contain only biodegradable items?
a. Grass, flowers and leather
b. Grass, wood and plastic
c. Fruit peels, cake and lime juice
d. Cake, wood and grass

Solution:

a) Grass, flowers and leather
c) Fruit peels, cake and lime juice
d) Cake, wood and grass

Above all are the groups that contain only biodegradable items. Since plastic is not a biodegradable substance, that group cannot be considered as a biodegradable.

 Q.5Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?

Solution:

The ozone layer is a protective cover for the earth. It prevents harmful UV rays from entering the earth as these rays harmful and can result in skin cancer. But the air pollutants like chlorofluorocarbons (CFCs) are the main reason for the depletion of the ozone layer. Too much of UV rays are harmful to plants as they affect photosynthesis, destroy planktons and decomposers. These are the reasons why damage of ozone layer is a cause of concern.

Q.6 Why are bacteria and fungi called decomposers? List any two advantages of decomposers to the environment. [Delhi]
Answer. Bacteria and fungi breakdown the dead remains and waste products of organisms. These micro organisms are called the decomposers as they breakdown the complex organic substances into simple inorganic substances that go into the soil and are used up once more by the plants.
Two advantages of decomposers to the environment are as follows:

1. Decomposers feed, on the dead bodies of plants and animals. They return the simple components to soil and help in making the steady state of ecosystem by recycling of nutrients. They, therefore, create a balance in the environment.
2. They also act as scavengers or cleansing agents of the atmosphere.

Q.7. Describe how decomposers facilitate recycling of matter in order to maintain balance in the ecosystem. [Foreign]
Answer. Decomposers are micro organisms that obtain energy from the chemical breakdown of dead organisms of animals or plants. These micro organisms breakdown the complex organic substances of dead organisms into simple inorganic substances that go into the soil and are used up once more by the plants. Decomposers thus, help in recycling of matter.

 How is ozone formed in the upper atmosphere? Why is the damage of ozone layer a cause of concern to us? State a cause of this damage. [Delhi(C)]
Answer. Ozone is formed in upper atmosphere by the reaction of ultraviolet (UV) radiations on oxygen (0₂) molecule.
The damage to ozone layer is a cause of concern to us as due to its damage, more ultraviolet rays reach the earth’s surface causing various health hazards.

A cause of this damage is the presence of large amount of chlorofluorocarbons in the atmosphere.

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Q.1 (a) Define tidal energy.
(b) Explain how the tidal energy is harnessed and write one limitation of the use of tidal energy.
Answer.
(a) Tidal energy: The energy produced by the surge of ocean water during high and low tides due to difference in sea-levels is called tidal energy. The high and low tides occur due to the gravitational pull of the moon. This causes enormous movement of water.
(b) Tidal energy is harnessed by constructing a dam near the shores. During the high tides water flows into the dam and during the low tides, water flows out. This flowing water rotates the turbine, present at the opening of the dam and produces electricity.

Q.2 Distinguish between renewable and non-renewable sources of energy. Also give an example of each of these sources.
answer.

Q.3 What are the advantages of nuclear energy?
answer. Advantages of nuclear energy are:

1.  A small quantity of nuclear fuel is needed to produce a large amount of useful energy.
2.  Nuclear power plant produces less atmospheric pollution than thermal power plants, if the nuclear fission reaction is performed properly.
3.  Small amount of nuclear fuel can run a nuclear power plant over a long period of time. There is no need of inserting the nuclear fuel in the nuclear reactor again and again in a short period as in case of thermal power plant.

Q.4. What is a solar cell panel? Mention any three of its applications.
answer. A large number of solar cells combined in an arrangement to obtain large electrical power is called solar cell panel.
Applications of solar cell panel are:
It provides the electric power for the:

1. working of artificial satellites stationed in outer space,
2.  running of irrigation water pumps by the farmers in rural areas,
3.  street lighting in remote areas.

Q.5 List any three hazards of nuclear waste. How does the disposal of nuclear waste pose a problem for the plant and animal life?
answer. Hazards of nuclear wastes are:

1.  Nuclear waste contains radioactive substances which emit harmful nuclear radiations.
2. There is a high risk of environmental contamination.
3. It is highly toxic.
   Effect of nuclear waste on plant and animal life is:
   The radiations emitted from the nuclear waste penetrate deep inside the human or animal body where they can damage biological cells thereby initiate cancer or causes genetic disease.
   Increased mortality of plants, soil invertebrates and mammals and reproductive losses in plants and animals have also been observed.

Q.6 (a) What is geothermal energy?
(b) What are the advantages of wind energy?
answer.
(a) The heat energy obtained from the molten rocks formed in the deeper hot regions inside the earth are called geothermal energy.
(b) Advantages of wind energy are:

1.  It is an inexhaustible source of energy.
2. It does not cause any environmental pollution.
3.  It is available at free of cost.

 Q.7 Mention any four limitations in harnessing wind energy on a large scale.
answer. Limitations in harnessing wind energy are:

1.  Speed of wind is not available at all time and at all places.
2. To establish the wind energy farm, a large area of land is needed.
3.  Speed of wind should be higher than 15 km/h to harness the wind energy.
4. Construction of windmill and its installation is very expensive.

Q.8 Solar cooker takes more time as compared to the LPG to boil potato or rice, yet Kunal uses solar cooker for such type of cooking:
(i) Why does Kunal uses Solar cooker instead of LPG? Give reasons for your answer.
(ii) Name the phenomenon which is responsible for obtaining high temperature in solar cooker.
Answer.
(a)(i) There are no energy losses while cooking on the solar cooker as the food gets cooked in a controlled environment whereas cooking on the LPG leads to maximum percentage of energy loss.
(ii) Temperature controlled cooking retains the nutrient value of the food.
(iii) Using the solar cooker, LPG can be served which result reduction in the emission of  CO₂.
(iv) It saves a lot of prestigious time which is normally consumed for cooking purpose.
(b) Greenhouse effect.

Q.9 Reena’s father works with a company that builds dams. Once he took her to the site where a dam was being built. Reena saw a group of people sitting there and shouting slogans against the building of dam. She talked the group of people and asked them about their problems and then discussed it with her father. She then tried to convince the people to talk with the authorities and come to an amicable solution. The discussion was successful. Reena’s father was very proud of his daughter. Now answer the following questions:
(i) Why was Reena’s father proud of his daughter?
(ii)Why was the group of people protesting against the building of dam?
(iii) Reena’s contribution to the peaceful resolution of the conflict proved to boon for many citizens of the country. How?
Answer.
(i) Because she convinced the people by explaining them the advantage of constructing dam and come with a solution of rehabilitation of displaced peoples. So the contribution to the peaceful resolution of the conflict make Reena’s father proud of his daughter.
(ii)The group of people protesting against the building of dam because of following disadvantages
(a) A large area of agricultural land and human habitation are sacrificed as it get submerged at the dam site.
(b) Large ecosystems are destroyed when submerged under water.
(c) The decomposition of vegetation under anaerobic condition produces methane gas which is also a greenhouse gas.
(iii)(a) The citizens are not affected by flood as it can be controlled by storing the water behind the dam.
(b) Farmers get benefited as water for irrigation is available for the whole year.
(c) Low cost of production of electricity gives monetary gain which is a boon to citizens.

Q.10 Bio gas is an excellent fuel. Justify the statement by giving two reasons. Mention the main constituents of bio gas along with its percentage.
Answer. 
(i) It burns without smoke and leave no residue therefore causes no atmospheric pollution.
(ii)Its heating capacity is high, i.e. it has high calorific value. Main constituents of bio gas: The composition of bio gas varies depending upon the nature of organic matter feeding in’the digester and advanced waste treatment technology. The typical composition of bio gas is
Methane                                50 – 75%
Carbon dioxide                     25 – 50%
Nitrogen                                   0 – 10%
Hydrogen                                 0 – 1%
Hydrogen sulphide                0 – 3%

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