Lakhmir Singh Manjit Kaur Biology 2020 2021 Solutions for Class 10 Science Chapter 6 Management Of Natural Resources are provided here with simple step-by-step explanations. These solutions for Management Of Natural Resources are extremely popular among Class 10 students for Science Management Of Natural Resources Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the Lakhmir Singh Manjit Kaur Biology 2020 2021 Book of Class 10 Science Chapter 6 are provided here for you for free. You will also love the ad-free experience on Meritnation’s Lakhmir Singh Manjit Kaur Biology 2020 2021 Solutions. All Lakhmir Singh Manjit Kaur Biology 2020 2021 Solutions for class Class 10 Science are prepared by experts and are 100% accurate.
Page No 258:
Question 1:
Name two fossil fuels.
Answer:
Petroleum and coal are two fossil fuels.
Page No 258:
Question 2:
Name the major programme started to replenish forests.
Answer:
Silviculture is the major programme started to replenish forests.
Page No 258:
Question 3:
Apart from the availability of forest products, name two other things which are affected by the destruction of forests.
Answer:
Apart from the availability of forest products, habitat of wild animals and soil conservation also get affected due to the destruction of forests.
Page No 258:
Question 4:
Name the rivers with which the following dams are associated :
(a) Tehri Dam
(b) Sardar Sarovar Dam
(c) Bhakra Dam
Answer:
(a) Tehri Dam: Bhagirathi river
(b) Sardar Sarovar Dam: Narmada river
(c) Bhakra Dam : Satluj river
Page No 258:
Question 5:
Name two factors which can be used to find whether river water has been contaminated.
Answer:
Presence of coliform bacteria in the river water as well as the pH of the river can be used to find whether river water has been contaminated.
Page No 258:
Question 6:
Name the bacteria whose presence in water indicates the contamination with disease-causing micro-organisms.
Answer:
The presence of Coliform bacteria in water indicates the contamination with disease-causing micro-organisms.
Page No 258:
Question 7:
With which process are the following ancient structures associated?
Kulhs, Eris, Surangams, Kattas, Pynes
Answer:
Kulhs, Eris, Surangams, Kattas, Pynes are associated with rainwater harvesting.
Page No 258:
Question 8:
Which fossil fuel is conserved :
(a) when we save on electricity?
(b) when we use bicycle for covering short distances instead of a motorbike?
Answer:
(a) Coal is conserved when we save electricity.
(b) Petroleum is conserved when we use a bicycle for covering short distances instead of a motorbike.
Page No 258:
Question 9:
What is the main purpose of rainwater harvesting?
Answer:
The main purpose of rainwater harvesting is to save and conserve water for future use.
Page No 258:
Question 10:
What is the name of the process in which rainwater falling on the earth is stopped from flowing and made to percolate into the ground?
Answer:
The name of the process in which the rainwater falling on the Earth is stopped from flowing and made to percolate into the ground is known as rainwater harvesting.
Page No 258:
Question 11:
Name the most common practice of recharging ground water.
Answer:
Rainwater harvesting is the most common practice of recharging ground water.
Page No 258:
Question 12:
The pH of a river water sample as measured by pH paper is found to be 6. What does it tell us about water?
Answer:
It means that river water is polluted with acidic wastes.
Page No 258:
Question 13:
Name the person who is most remembered for the protection of Khejri trees in Rajasthan.
Answer:
Amrita Devi Bishnoi is most remembered for the protection of Khejri trees in Rajasthan.
Page No 258:
Question 14:
State whether the following statement is true or false :
Chipko Andolan was associated with the conservation of wild animals such as tigers and lions.
Answer:
False. Chipko Andolan was associated with the conservation of trees.
Page No 258:
Question 15:
Write the full names of (a) CFL, and (b) CFC.
Answer:
(a) CFL: Compact Fluorescent Lamp
(b) CFC: Chlorofluorocarbon
Page No 258:
Question 16:
Choose one term from the following which include all others :
coal, natural gas, fossil fuels, petroleum
Answer:
Fossil fuels include all the other given terms, i.e. coal, natural gas and petroleum.
Page No 258:
Question 17:
Why is the process of 'reuse' better than that of 'recycling'?
Answer:
When we 'reuse' a product, we use the same thing without processing. Thus, it is better than the process of 'recycling'.
Page No 258:
Question 18:
Name a clean gaseous fuel other than LPG and natural gas.
Answer:
Apart from LPG and natural gas, biogas is a clean gaseous fuel.
Page No 258:
Question 19:
Fill in the following blanks with suitable words :
(a) LPG is a ........... fuel but biogas is not a..........fuel.
(b) Glaciers are a source of .............
(c) One of the main aim of management of forests and wildlife is to conserve the ........... which we have inherited.
(d) Khadin is a traditional ............... harvesting system in Rajasthan.
(e)When a fuel burns in an insufficient supply of air, then some poisonous gas called ......... is also produced.
Answer:
a) LPG is a fossil fuel but biogas is not a fossil fuel.
(b) Glaciers are a source of water.
(c) One of the main aim of management of forests and wildlife is to conserve the biodiversity, which we have inherited.
(d) Khadin is a traditional rainwater harvesting system in Rajasthan.
(e)When a fuel burns in an insufficient supply of air, then some poisonous gas called carbon monoxide is also produced.
Page No 259:
Question 20:
What is meant by "sustainable development"?
Answer:
"Sustainable development" is a kind of development that fulfils the basic needs of the present generation and also preserves the natural resources for the future generations.
Page No 259:
Question 21:
What is silviculture? What are its advantages?
Answer:
Silviculture is the programme that aims to grow more trees and plants in order to replenish forests.
Following are the advantages of silviculture:
(a) It prevents flood and soil erosion.
(b) It maintains the water cycle.
(c) It helps in wildlife conservation by increasing the area of the earth under the forests.
(d) It provides different raw materials for industries.
Page No 259:
Question 22:
Write a short note on 'Chipko Andolan' (Hug the Trees Movement).
Answer:
'Chipko Andolan' was started by the common people to conserve the forests. The movement originated in a remote village named Reni, in Garhwal. In this movement, when the workers of a contractor came to cut the trees, in absence of the men of the village, all the women clasped the tree trunks in order to save the trees.
Page No 259:
Question 23:
Why should we conserve forests and wildlife?
Answer:
The forests and wildlife should be conserved in order to conserve our biodiversity, which we have inherited. The loss of forests and wildlife will result in the loss of forest ecosystem and ecological balance.
Page No 259:
Question 24:
Describe briefly the 'khadin' system of rainwater harvesting practised in Rajasthan.
Answer:
The 'khadin' system of rainwater harvesting practised in Rajasthan has a long earthen embankment known as bund, which is built across the edges of sloping farmlands. The rain water flows down the slope and is stopped by bund. It then forms a reservoir. The water in the reservoir seeps into the land and can be used for growing crops.
Page No 259:
Question 25:
What measures would you take to conserve electricity in your house?
Answer:
Electricity can be conserved in our houses using some measures. They are:
- Switching off the electrical appliances when not needed
- Using electrical efficient appliances like CFL.
Page No 259:
Question 26:
Although coal and petroleum are produced by the degradation of biomass, even then we need to conserve them. Why?
Answer:
Coal and petroleum are the fossil fuels and their supply is limited on the Earth. Therefore, we need to conserve them. They are made by the degradation of biomass, but this practise takes millions of years.
Page No 259:
Question 27:
Is water conservation necessary? Give reasons.
Answer:
Yes, it is very important to conserve water as it is the basic necessity of all living beings. Humans, plants and animals, all need water for survival. But, the available water on the Earth is limited. Therefore, it should be conserved.
Page No 259:
Question 28:
Name the products of combustion of fossil fuels like coal and petroleum products. How do they affect us and our environment?
Answer:
Carbon dioxide, sulphur dioxide, nitrogen oxide and water are produced by combustion of fossil fuels like coal and petroleum products. Their incomplete combustion produces carbon monoxide.
All of them, except water, are harmful for us and our environment. For example, sulphur oxide and nitrogen oxide, when mixed with water, cause acid rains. Increase in the carbon dioxide concentration in air causes greenhouse effect.
Page No 259:
Question 29:
Why should fossil fuels like coal and petroleum be used judiciously?
Answer:
Coal and petroleum are fossil fuels that require millions of years to be formed. They are natural resources and are limited in supply. Once exhausted, they cannot be formed again in a short time. Therefore, fossil fuels like coal and petroleum should be used judiciously.
Page No 259:
Question 30:
What are the three R's to save the environment? Explain with one example of each.
Answer:
The three Rs are reduce, recycle and reuse.
The term 'reduce' aims at lowering the usage of natural resources to avoid wastage. For example, using less electricity.
The term 'recycle' aims at using the discarded items by recycling them. For example, recycling paper and plastic and sending them to the respective industries for the formation of new paper and plastic.
The term 'reuse' means using the same thing again and again. For example, using a paper bag over and over again.
Page No 259:
Question 31:
What are the main uses of coal and petroleum products?
Answer:
Following are the main uses of coal and petroleum products:
- Coal is used in homes and industries as a fuel. It is also used to generate electricity in power plants.
- Petroleum products (such as petrol and diesel) are used as fuels in vehicles. Other products (like kerosene and LPG) are used as domestic fuels for cooking.
Page No 259:
Question 32:
State any five steps to reduce the consumption of coal and petroleum products.
Answer:
Coal is used to generate electricity and petroleum products are used as a fuel. The consumption of coal and petroleum products can be reduced in the following ways:
- Use stairs instead of lift to save electricity.
- Use bicycle to save fuel, like petrol.
- Use solar cooker to save cooking fuel, like LPG.
- Use public transport to save fuel.
- Switch off lights, fans and other electrical appliances when not needed to save electricity.
Page No 259:
Question 33:
Explain why, despite good rains, we are not able to meet the demand for water of all the people in our country.
Answer:
Despite of good rains, we are not able to meet the demands for water of all the people in our country. This is because our population is increasing on a fast pace. Also, high yielding variety of crops require more water for irrigation, in urban areas people consume more water and the industrial waste and untreated sewage is discarded into rivers making it contaminated. All these things need large amount of water; hence, causing water scarcity.
Page No 259:
Question 34:
Give one example to show how the participation of local people can lead to the efficient management of forests.
Answer:
Chipko Andolan shows how the participation of local people can lead to the efficient management of forests. It was started by the common people to conserve the forests. The movement originated in a remote village named Reni, in Garhwal. In this movement, when the workers of a contractor came to cut the trees in the absence of the men of the village, all the women clasped the tree trunks with their arms, in order to save the trees.
Page No 259:
Question 35:
Explain briefly, how rainwater harvesting is done from open spaces around the buildings in city areas.
Answer:
For rainwater harvesting from open spaces around the buildings in city areas, percolation pits are constructed and covered with concrete slabs having holes in it. They are connected to a recharge well via a pipe. The rain water goes into the percolation pit through the holes of the slab cover. It gets filtered in the pit and enters the recharge well via an outlet pipe and then, slowly, seeps into the soil.
Page No 259:
Question 36:
(a) What is a natural resource? Name three important natural resources.
(b) Why do we need to manage our natural resources?
Answer:
(a) Natural resources are the things present in the environment that can be used by humans. Three important natural resources are water, fossil fuels, like coal and petroleum, and forest and wildlife.
(b) We need to manage our natural resources. The reasons for this are given below:
- They are limited in amount. We need to manage them so that they can fulfil the need of the present as well that of the coming generations.
- This will prevent their exploitation for short term gain.
- This will ensure equal distribution of natural resources so that everyone can benefit from their development.
- This will also minimise the damage to the environment, which is caused during the extraction and usage of natural resources.
Page No 259:
Question 37:
(a) State the advantages of constructing dams across the rivers.
(b) Describe some of the problems associated with the construction of dams.
Answer:
(a) Following are the advantages of constructing dams across the rivers:
- They can store excess water, thereby preventing floods.
- Water from the dams can be used for the irrigation of crops via a network of canals.
- After a suitable treatment, people of towns and cities get dam water through pipelines, for usage.
- Water falling from the dams is used to generate electricity in hydropower plants.
- Social problems: It makes many people homeless, by submerging large areas of human- settlements, thereby causing a social issue.
- Environmental problems: It causes deforestation and loss of biodiversity by submerging large varieties of plants and animals. This creates an ecological imbalance.
- Economic problems: This is an issue raised by many people who consider that construction of dams needs large amount of public money and there are no proportionate benefits.
Page No 259:
Question 38:
(a) Name any five sources of water (other than rivers)
(b) Describe how, the water of river Ganga has been highly polluted.
Answer:
(a) The sources of water other than rivers are rains, oceans, lakes, glaciers and wells.
(b) The water of river Ganga has been polluted by various human activities like bathing, washing of clothes, immersion of ashes of dead bodies and unburnt corpses in the river. The untreated sewage and industrial waste is also discarded in the river. Chemical effluents from the industries are also discharged in it. More than hundred towns and cities lie along its way, which discharge their waste in it. This has harmed the aquatic life of this river.
Page No 259:
Question 39:
(a) Name the major industries which are based on forest produce.
(b) State the main aim of the management of forests and wildlife.
(c) Name the four main stakeholders in the management of forest resources.
Answer:
(a) The major industries that are based on forest produce are paper mills as well as industries dealing in timber, lac and sports equipment.
(b) The main aim of the management of forests and wildlife is to conserve our inherited biodiversity in order to maintain the ecological balance.
(c) The four main stakeholders in the management of forest resources are the people, the forest department, the industrialists and the forest and wildlife activists.
Page No 259:
Question 40:
(a) What is meant by rainwater harvesting? Name some of the ancient structures used for rainwater harvesting by the rural people.
(b) What are the various advantages of water stored in ground?
Answer:
(a) Rainwater harvesting is the method of collecting rain water so that it can percolate in the soil more efficiently. The ancient structures used for rainwater harvesting by the rural people are Khadin in Rajasthan, Bandharas and Tals in Maharashtra, and Ahars in Bihar.
(b) Following are the various advantages of water stored under the ground:
- It does not evaporate.
- It spreads out to recharge wells and provides moisture to the crops.
- It does not promote breeding of mosquitoes.
- It is not contaminated by human and animal wastes.
- It can be utilised by the local population.
Page No 259:
Question 41:
The Bishnoi community of Rajasthan is associated with the conservation of :
(a) coal and petroleum
(b) forests and wildlife
(c) water resources
(d) abiotic environment
Answer:
(b) forests and wildlife
Amrita Devi Bishnoi, along with the Bishnoi community, worked for the protection of wildlife and forests.
Page No 259:
Question 42:
The Chipko Andolan is associated with :
(a) Tigers
(b) Turtles
(c) Trees
(d) Tomatoes
Answer:
(c) Trees
The Chipko Andolan is associated with the conservation of trees. It was initiated to protect the trees from being cut.
Page No 259:
Question 43:
Amrita devi Bishnoi was associated with :
(a) preventing the custom of child marriage in Rajasthan
(b) campaign to save the girl child
(c) conservation of cultural heritage of Rajasthan
(d) conservation of forests and wildlife
Answer:
(d) conservation of forests and wildlife
Amrita devi Bishnoi was associated with the conservation of forests and wildlife.
Page No 259:
Question 44:
One of the following is not a direct stakeholder in the management (or conservation) of forests. This is :
(a) the people who have paper mills.
(b) the people who run the forest department
(c) the people who campaign for the conservation of forests
(d) the people who live in urban areas
Answer:
(d) the people who live in urban areas
People living in urban areas do not directly contribute in the management of forests. Thus, they are not the direct stakeholders.
Page No 259:
Question 45:
The river water is said to be polluted with acidic wastes if the pH of river water is :
(a) zero
(b) above 7
(c) below 7
(d) exactly 7
Answer:
(c) below 7
Acidic substances have less than 7 pH.
Page No 260:
Question 46:
The major programme started to replenish the damaged forests is called :
(a) horticulture
(b) tissue culture
(c) agriculture
(d) silviculture
Answer:
(d) silviculture
Silviculture is the major programme that was started to replenish the damaged forests.
Page No 260:
Question 47:
With which tree Amrita Devi Bishnoi is associated?
(a) khajoor
(b) khejrali
(c) khejri
(d) keekar
Answer:
(b) khejrali
Amrita Devi Bishnoi is associated with the conservation and protection of khejrali trees.
Page No 260:
Question 48:
One of the following does not contribute in producing acid rain. This one is :
(a) sulphur dioxide
(b) carbon dioxide
(c) nitrogen oxides
(d) carbon monoxide
Answer:
(d) carbon monoxide
All other gases, except carbon monoxide, react with water to produce acid. Thus, they contribute to acid rain.
Page No 260:
Question 49:
The poisonous gas which reduces the oxygen-carrying capacity of blood to a large extent is :
(a) SO2
(b) NO
(c) CO
(d) CO2
Answer:
(c) CO
Carbon monoxide, i.e. CO, binds with red blood cells and reduces its oxygen carrying capacity.
Page No 260:
Question 50:
Which of the following is not an ancient water harvesting structure?
(a) kattas
(b) sargam
(c) kulhs
(d) surangams
Answer:
(b) sargam
Sargam is not an ancient harvesting structure.
Page No 260:
Question 51:
Snakes are killed in large numbers because :
(a) they are very poisonous
(b) they kill rats
(c) their skin is expensive
(d) they damage the crops
Answer:
(c) their skin is expensive
Snakes are killed for their skin, which is very expensive. Their skin is sold in markets.
Page No 260:
Question 52:
Which of the following is not a fossil fuel?
(a) LPG
(b) natural gas
(c) biogas
(d) CNG
Answer:
(c) Biogas
Biogas does not require millions of years to form. Therefore, it is not a fossil fuel.
Page No 260:
Question 53:
Which of the following is not a natural resource?
(a) soil
(b) water
(c) electricity
(d) natural gas
Answer:
(c) electricity
Electricity is a man-made resource.
Page No 260:
Question 54:
The most rapidly dwindling natural resource in the world is :
(a) water
(b) soil
(c) sunlight
(d) forests
Answer:
(d) forests
Forests are being cut on a large scale. Therefore, they are the most rapidly dwindling natural resource in the world.
Page No 260:
Question 55:
Which of the following is not a natural resource?
(a) snake
(b) wind
(c) wooden house
(d) mango tree
Answer:
(c) wooden house
Wooden houses are made by man. Hence, it is not a natural resource.
Page No 260:
Question 56:
The three R's which can help us to conserve natural resources for long term use are :
(a) recycle, regenerate, reuse
(b) reduce, regenerate, reuse
(c) reduce, reuse, redistribute
(d) reduce, recycle, reuse
Answer:
(d) reduce, recycle, reuse
The three R's, i.e. reduce, recycle, reuse, can help us to conserve natural resources for a long-term use.
Page No 260:
Question 57:
The main reason for the abundant coliform bacteria in the water of river Ganga is :
(a) immersion of ashes of the dead into the river
(b) washing of clothes on the banks of river
(c) discharge of industrial wastes into river water
(d) disposal of unburnt corpses into river water
Answer:
(d) disposal of unburnt corpses into river water
The coliform bacteria is present in human intestine. Its presence shows contamination. The main reason for the presence of abundant coliform bacteria in river Ganga is the disposal of unburnt corpses into the river water.
Page No 260:
Question 58:
The pH of a sample of water collected from a river is found to be in the range of 3.5 to 4.5. The most likely reason for this is the waste being discharged into the river from a :
(a) soap and detergent manufacturing factory
(b) car battery manufacturing factory
(c) alcohol manufacturing factory
(d) plastic cups moulding factory
Answer:
(b) car battery manufacturing factory
Such factories produce acidic wastes that make the river water acidic.
Page No 260:
Question 59:
Which of the following statement is incorrect?
(a) economic development is linked to environmental conservation
(b) sustainable development meets the current basic human needs and also preserves resources for future generations
(c) sustainable development does not take into consideration the viewpoints of all stakeholders
(d) sustainable development is a long planned and persistent development
Answer:
(c) Sustainable development does not take into consideration the viewpoints of all stakeholders.
Page No 260:
Question 60:
Arabari forest of Bengal is dominated by :
(a) Teak
(b) Sal
(c) Bambooo
(d) Mangroove
Answer:
(b) Sal
Sal trees dominate Arabari forest of Bengal.
Page No 260:
Question 61:
Groundwater will not be depleted due to :
(a) process of afforestation
(b) establishing thermal power plants
(c) process of deforestation
(d) cultivation of high yielding varieties of crops
Answer:
(a) process of afforestation
Afforestation prevents the water from immediately rushing into the rivers. Due to this, water can seep in the ground and replenish the ground water.
Page No 260:
Question 62:
Ahars, Kattas, Bhundhis and Khadins are the modes of :
(a) grain storage
(b) soil conservation
(c) water harvesting
(d) cold storage
Answer:
(c) water harvesting
Ahars, Kattas, Bhundhis and Khadins are the ancient methods of water harvesting.
Page No 260:
Question 63:
Which of the following combination of terms has no fossil fuel?
(a) wind, ocean, coke
(b) kerosene, tide, wind
(c) wood, wind, sun
(d) petrol, wood, sun
Answer:
(c) wood, wind, sun
They all are natural resources, which are not fossil fuels.
Page No 260:
Question 64:
The use of one of the following is eco-friendly. This one is :
(a) cars for transportation
(b) polybags for shopping
(c) windmills for generating power
(d) dyes for colouring clothes
Answer:
(c) windmills for generating power
Windmills use wind to generate electric energy. They do not create any kind of pollution. Thus, they are eco-friendly.
Page No 260:
Question 65:
Khadins are used in Rajasthan to :
(a) hold water for irrigation
(b) recharge groundwater
(c) promote soil erosion
(d) trap wild animals
Answer:
(b) recharge groundwater
Khadins are used in Rajasthan to conserve water.
Page No 261:
Question 66:
In a village, farmers started cultivating crops all around a lake which was always filled with water. They added lot of materials W to the soil in their fields to increase the yield of crops. Soon they found that the whole surface of water in the lake was covered with a green layer made up of tiny organisms X. After some time, the fish present in the lake started dying in large numbers because they could not get sufficient Y due to a process Z which had occurred in lake water and drained out all the Y present in the water of lake.
(a) What do you think materials W are?
(b) Name (i) X, and (ii) Y.
(c) What is the process Z known as?
(d) What happens during the process Z which uses up all the Y present in lake water?
(e) What does this example tell us about the use of materials like W?
Answer:
(a) W refers to the fertilisers.
(b) X is Algae and Y is oxygen.
(c) The process Z is known as eutrophication.
(d) During the process of eutrophication (Z), when the alga (Y) dies, the bacteria present in the water decay the alga.
(e) This example shows that excessive use of fertilisers (W) is bad for the environment.
Page No 261:
Question 67:
There were lot of organisms A in the crop fields in an area. These organisms used to feed on organisms B also present in the crop fields but which damaged the standing crops. One day some people arrived in the fields and killed all the organisms A so that they could remove their C for making fancy items which were in great demand. Due to large scale killing of A, the population of B increased too much damaging all the crops in the area and causing a famine-like situation. Apart from A, there is another organism D which can also kill and eat B. Name A, B, C and D.
Answer:
Organism A is a snake as it feeds on rats and it is being killed to make fancy items.
Organism B is a rat.
Organism C is the skin of a snake that is used in making fancy items.
Organism D is a cat as it also feeds on rats (B).
Page No 261:
Question 68:
There are two important fuels A and B both of which are extracted from deep inside the earth. Fuel A is a thick, dark, foul smelling liquid whereas fuel B is a black solid. Combustion of both the fuels produces products, C, D, E and F. The product C makes the rainwater only slightly acidic but it is mainly responsible for causing global warming. The product D is neither acidic nor basic. It is harmless and does not affect the environment in any way. Both E and F attack breathing system of humans and are mainly responsible for causing acid rain. In addition to combustion of fuels A and B, the product F is also formed when lightning occurs in the sky.
(a) What are (i) fuel A, and (ii) fuel B?
(b) Name (i) C (ii) D (iii) E, and (iv) F
(c) What is the process of formation of F during lightning known as?
(d) Which fuel is supposed to be exhausted sooner : A or B?
(e) Which fuel is mostly used for generating electricity at thermal power plants?
Answer:
(a) (i) Fuel A is petroleum and (ii) fuel B is coal.
(b) (i) C is carbon dioxide, (ii) D is water, (iii) E is sulphur dioxide and (iv) F is nitrogen oxide.
(c) The process of formation of F during lightning is known as natural nitrogen fixation.
(d) Fuel A is supposed to be exhausted sooner.
(e) Fuel B, i.e. coal, is mostly used for generating electricity at thermal power plants.
Page No 261:
Question 69:
A man bought a device X which could cook pulses, vegetables and rice without using any fuel like wood, coal, kerosene or LPG, etc. This device did not work at night. It also took a lot of time for cooking.
(a) Name the device X.
(b) What is the source of energy which cooks food in this device?
(c) What is the name of the process which traps energy in this device?
(d) State one advantage (other than saving on fuel) or using such a device for cooking food.
Answer:
(a) Device X is a solar cooker.
(b) Solar energy is the source of energy that cooks food in this device.
(c) Greenhouse effect is the process that traps energy in this device.
(d) The advantage of this technique is that it does not cause any pollution or harm to the environment.
Page No 261:
Question 70:
A person buys two electrical devices P and Q for lighting purposes in his house. The device P consumes only 5 units of electricity in a month but device Q consumes 15 units of electricity in a month when used for the same number of hours daily. The device Q wastes a lot of electricity by radiating energy C but P does not do so.
(a) What type of device is (i) P, and (ii) Q?
(b) Name one component which is present in Q but not in P.
(c) Name the energy C.
(d) Which device is more energy efficient : P or Q?
(e) Which fossil fuel is most likely to be conserved if all of us switch over to devices like P?
Answer:
(a) (i) P is a CFL (Compact Fluorescent Lamp), and (ii) Q is a filament type bulb.
(b) Filament is present in a bulb, not in CFL.
(c) Energy C is heat energy.
(d) P is more energy efficient.
(e) Coal will be conserved if all of us switch over to devices like P (CFL). This is because it is used in generating electricity.
View NCERT Solutions for all chapters of Class 10