Source Of Energy Class 10 Important Questions Science Chapter 14

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Source Of Energy Class 10 Important Questions with Answers Science Chapter 14

Source Of Energy Class 10 Important Questions Very Short Answer Type

Question 1.
What is the minimum speed of wind required by a wind mill to maintain the necessary speed of turbine in electric generator?  (AI 2008)
Answer:
The speed of wind should be more than 15 km/h.

Question 2.
List two nutrients that the slurry left behind in the biogas plant contain.  (CBSE 2011)
Answer:
Nitrogen and phosphorous.

Question 3.
List two practical uses of biogas in rural areas.  (CBSE 2011)
Answer:

  1. It is an excellent fuel which burns without smoke with high heating capacity,
  2. It is also used for lighting.

Question 4.
Name one fuel used in nuclear reactor.  (CBSE 2012)
Answer:
Uranium – 235.

Question 5.
Name the reaction responsible for large energy production in the sun. (CBSE 2012)
Answer:
Nuclear fusion.

Question 6.
What is acid rain?  (CBSE 2013)
Answer:
The rain containing the acidic oxides such as oxides of carbon, nitrogen and sulphur.

Question 7.
Mention the minimum temperature difference required between surface water and water at a depth of upto 2 km in an ocean thermal energy plant.   (CBSE 2013)
Answer:
The minimum difference in the water at the surface and the water at the bottom should be of 20 degree Celsius or 293K.

Question 8.
Write the name of the substance whose vapours are used to run the turbine of the generator of ocean thermal energy plant.   (CBSE 2013)
Answer:
Ammonia.

Question 9.
List two non-conventional sources of energy.  (CBSE 2014)
Answer:

  1. Geothermal
  2. solar
  3. biomass
  4. water
  5. wind are the non-conventional sources of energy

Question 10.
Name the part of a biogas plant where reactions take place in the absence of oxygen.  (CBSE 2014)
Answer:
Digester chamber.

Question 11.
Name the kind of energy possessed by wind and the device used to harness it.
Answer:
Kinetic energy, wind mill.

Question 12.
A black surface absorbs more heat radiations as compared to a white or a reflecting surface under identical conditions. List two solar devices which make use of this property in their design.   (CBSE 2014)
Answer:

  1. Solar water heater
  2. solar cooker.

Question 13.
Name any two elements that are used in fabricating solar cells.   (CBSE 2014)
Answer:
Germanium-arsenic
or
germanium-silicon.

Question 14.
Name any two fossil fuels.   (CBSE 2015)
Answer:
Coal and petroleum are two fossil fuels.

Question 15.
What are the features of a good fuel?   (CBSE 2015)
Answer:
A good fuel should have the following features:

  • high calorific value
  • non-polluting,
  • easy to transport and easily available,
  • has moderate ignition temperature.

Question 16.
Mention the purpose of blackening the interior of a solar cooker.   (CBSE 2015)
Answer:
The black colour absorbs more heat than any other color and hence to increase the temperature in the closed cooker it is painted with the black colour.

Source Of Energy Class 10 Important Questions Short Answer Type

Question 1.
How is the increase in demand of energy affecting our environment adversely?  (CBSE 2008)
Answer:
Due to increasing demand of energy the available sources of energy are depleting in fast rate and thus creating more pollution.

Question 2.
Write two advantages of classifying energy source as renewable and non-renewable.   (CBSE 2008)
Answer:
Classification of renewable and non-renewable source of energy helps us to identify and discriminate the two and encourage the use of only renewable sources of energy. It makes us think and initiate to look for alternate source of energy and curb the use of non-renewable source of energy.

Question 3.
What is the importance of hydro power plants in India? How electric energy is generated in such plants? (CBSE 2008)
Answer:
India has many hilly terrains through which the rivers flow. Dams can be constructed on these rivers to produce electricity from hydroelectric power plants.

In such plants, water is collected at high rise dam, this water is allowed to fall down on the turbine (kinetic energy of water is transformed to mechanical energy in turbines). This turbines move with a magnet in and out of copper coil to produce electricity.

Question 4.
Which of the following is a renewable source?
Natural gas, Petroleum, Ground water, Coal.  (AI 2008)
Answer:
Ground water.

Question 5.
Discuss each for the extracting energy from:
(a) Winds
(b) Tides
Answer:
(a) Winds-Large area of land required to build wind farms, speed of wind should be above 15 km/h not possible all the time and at all the places.
(b) Tides-The sites where such high tide dams can be constructed are very few.

Question 6.
Which one of the following gases is the major constituent of bio-gas?
Carbon monoxide, Hydrogen, Methane, Carbon dioxide.   (AI 2008)
Answer:
Methane.

Question 7.
What are fossil fuels? Give two examples of fossil fuels.   (Foreign 2008)
Answer:
Fossil fuels are non-renewable source of energy formed millions of years ago.
Two examples of fossil fuels

  1. coal
  2. petroleum.

Question 8.
What is a solar cell panel? Write two advantages associated with such panels.   (Foreign 2008)
Answer:
It is a panel on which many solar cells are installed, which convert Spn’s energy into electrical energy.

Two advantages: Solar cell panels can be setup at remote places and secondly it has no moving parts, require less maintenance and work quite satisfactorily without the use of any focusing device.

Question 9.
List two main advantages associated with solar cells.  (CBSE 2008C)
Answer:

  1. It does not cause pollution.
  2. Though initial cost is high, electricity produced from solar cells is comparable free of cost to other sources.

Question 10.
How is energy generated in a nuclear fission reaction? Why is the large scale use of nuclear energy prohibitive? (CBSE 2008C)
Answer:
In nuclear power plants a nuclear fuel is bombarded with projectiles which break the nucleus of radioactive substances like uranium, radium, polonium and it splits the big nucleus to two different atoms releasing large amount of heat energy. This heat energy can be controlled and used to produce steam.

Large scale use of nuclear energy is prohibited because the nuclear fuel can be misused to form nuclear bomb, its leakage can cause dangerous radio-active pollution.

Question 11.
What is bio-gas? Why is bio-gas considered an ideal fuel for domestic use?   (CBSE 2009)
Answer:
Bio-gas is a mixture of methane, CO2, H2 and H2S produced by anaerobic fermentation of biomass.
Greenhouse effect.

Question 12.
(a) Distinguish between renewable and non-renewable source of energy.
(b) Choose the renewable source of energy.
Coal, Bio-gas, Sun, Natural gas.   (CBSE 2009)
Answer:
Renewable:

  1. It can be renewed again and again
  2. It will never get exhausted, e.g., water, Sun

Non-renewable:

  1. It cannot be renewed again and again
  2. It will soon get exhausted e.g., Coal, Petroleum

(b) Renewable source of energy are-Bio-gas, Sun and natural gas.

Question 13.
Describe how hydro energy can be converted into electrical energy? Write any two limitation of hydro energy. (AI 2009)
Answer:
Two limitations:

  1. Dams cannot be constructed at every place.
  2. Large area of agricultural land gets submerged under water.

Question 14.
List four limitations of the energy obtained from oceans.   (Foreign 2009)
Answer:

  1. Waves of same intensity are not obtained at all the places.
  2. The dams for tides can not be constructed at all the sites.
  3. Tides do not come throughout a day.
  4. Efficient commercial exploitation is difficult.

Question 15.
Biogas is considered to be a boon to the farmers. Give reasons.  (CBSE 2011)
Answer:

  • It is a clean and efficient fuel.
  • Can be used for lightning
  • It is made from the biowaste of plants and animals.
  • The spent slurry is a rich source of nutrient for plants and can be used as manure.
  • It does not produce poisonous gases.

Question 16.
What are the advantages of nuclear energy?  (CBSE 2011)
Answer:
The advantages of nuclear energy are:

  1. A very small amount of radioactive material can produce large amount of energy which can be controlled and converted into usable form e.g., 1 kg Uranium = 25 thousand tonnes of coal.
  2. It does not release any smoke or harmful gases in the air. Hence it can curb the global warming that is caused due to greenhouse effect.

Question 17.
Out of two solar cookers, one was covered with a plane glass slab and the other was left open. Which of the two solar cookers will be more efficient and why?  (CBSE 2011)
Answer:
The solar cooker covered with the glass is more effective as it produces the greenhouse effect in the cooker and increases the temperature effectively. The temperature required for cooking on the cooker cannot be attained by the open cooker and it cannot be used for the purpose.

Question 18.
List any three hazards of nuclear waste. How does the disposal of nuclear waste pose a problem for the plant and animal life?  (CBSE 2011)
Answer:
The three hazards of nuclear waste are:

  1. The nuclear waste releases harmful radiations and hence need safe disposal
  2. It is highly toxic in nature.
  3. If not disposed properly it may contaminate the environment.

The improper disposal of nuclear waste can cause threat to plants and animals in the following ways:
If any plant or animal gets exposed to these nuclear waste or nuclear radiations, the radiations can penetrate into the cells and can cause the genetic disorder and may also lead to cancer. The plants and animals will soon be abnormal and extinct.

Question 19.
(a) What is geothermal energy?
(b) What are the advantages of wind energy?  (CBSE 2011)
Answer:
(a) The heat energy obtained in the form of steam from under the earth’s crust is called geothermal energy.
(b) The advantages of wind energy are:

  • It is an inexhaustible source of energy
  • It is available free of cost
  • It is clean and does not cause any sort of pollution.

Question 20.
Mention why is it not possible to make use of solar cells to meet all our energy needs? State three reasons to support your answer. Also mention three uses of solar cells.   (CBSE 2012)
Answer:

  • Of limited availability of special grade semiconducting materials such as silicon and germanium.
  • Solar cells have lower efficiency as they depend entirely on intensity of solar radiation.
  • The process of manufacturing of solar cells is very expensive, silver used for interconnection of cells in the panel further adds to the cost.

Uses:

  1. The solar panels are used in space satellites and space probes.
  2. The remote areas where no electric wires can be installed the panels are used to light those areas.
  3. Scientists, researchers or explorers going in deep forest or in remote areas make use of these panels for all their explorations and research work.

Question 21.
Out of two elements A and B with mass number 2 and 235 respectively, which one is suitable for making.
(a) a nuclear reactor
(b) a hydrogen bomb?
Name the nuclear reaction involved in each case. Write one difference between the two types of nuclear reactions. (CBSE 2012)
Answer:
(a) Element B with mass 235 is used for nuclear reactor
(b) Element A with mass 2 is used for making of hydrogen bomb
Nuclear reaction in B is fission and in A is fusion.

In fission the heavy nucleus splits to form two small nuclei with large amount of heat along with the harmful radiations.

In fusion two small nuclei combine to form one big heavy nucleus and the energy released is tremendous with no other harmful radiations.

Question 22.
Distinguish between renewable and non-renewable sources of energy. Also give an example of each of these sources.  (CBSE 2013)
Answer:
Renew able/Inexhaustible:

  1. They are also called inexhaustible
  2. The energy source that will not finish and can be renewed or made again and again is called renewable source of energy e.g., sun, wind, water.

Non-renewable/Exhaustible:

  1. They are also called as exhaustible.
  2. The energy source that will finish and will get exhausted and cannot be made very soon or takes million of years for its formation e.g., fossil fuels-petrol, coal.

Question 23.
State the principle of working of ocean thermal energy conversion plant. Explain how the plant works? Write one essential condition for it to operate properly.   (CBSE 2013)
Answer:
Principle of working of OTEC: The water at the surface of the ocean is warmer than the water at deeper depths. This temperature difference can be used by Ocean Thermal Energy Conversion (OTEC) systems to generate electricity.

OTEC-It is Ocean Thermal Energy Conversion. These plants can operate if the temperature difference between water at the surface and water at depths up to 2 km is 293 K (20°C) or more. The warm surface water is used to boil a volatile liquid like ammonia. The vapour of the liquid is then used to run the turbine. The cold water from the depth is pumped up and condense vapour again to liquid.

Question 24.
Define fuel. List any two characteristics that you would look for in a good fuel.   (CBSE 2014)
Answer:
A substance that produces useful energy when it undergoes chemical reaction or nuclear reaction.
The fuel should be easy to handle and not produce any environmental pollution.

Question 25.
State any three reasons to justify that LPG is considered as an ideal fuel. (CBSE 2014)
Answer:
LPG can be considered as an ideal fuel because:

  1. It does not leave any pollution like smoke or residue after burning.
  2. It bums efficiently to give useful energy that can be handled.
  3. It is easy to handle, store and transport.

Question 26.
State any three advantages of charcoal over wood.  (CBSE 2014)
Answer:
Charcoal is better fuel than wood :

  1. It does not produce smoke on burning and is considered to be cleaner fuel than wood.
  2. It has higher caloric value as compared to wood.
  3. It can be easily transported and is convenient to handle.

Question 27.
Ramesh is a student of standard X. He organized many activities in his school to convey the students about the various advantages and disadvantage of using renewable and non-renewable sources of energy. Many students of the school took part and concluded about the best choices of energy sources on this basis.
Answer the following questions:
(i) What activities Ramesh might have had assigned for the students?
(ii) Name any two renewable sources of energy.
(iii) Which two values are reflected in Ramesh’s though and action?  (CBSE 2014)
Answer:
(i) Ramesh might have assigned the following activities: A research on global warming, its causes and effects, a survey on use of fossil fuels as compared to use of non-renewable energy. A Power Point presentation on the impacts of use of renewable and non-renewable sources.
(ii) Solar and wind energy
(iii) Ramesh shows his concern for the community and environment and wants to spread the awareness by shouldering the responsibility of being a responsible global citizen.

Question 28.
Megha asked her mother to install a solar water heater on the roof top. Her mother asked about the need of such installation. Megha convinced her mother and succeeded in setting up a solar water heater on her roof top.
(i) State one advantage of installing the solar water heater to Megha’s family and to the society.
(ii) What qualities of Megha are reflected in her action?
(iii) State one limitation in using solar water heater.  (CBSE 2014)
Answer:
(i) Solar water heater is just one time installation for the long time usage. Though the initial cost is high, the electricity generated is free of cost and need not pay any electricity bill for hot water.
(ii) A responsible citizen doing their bit to contribute in sustaining the environment.
(iii) It does not work on cloudy days and at night.

Question 29.
Mariyam made a solar cooker on her own. She used a white metallic box with a lid. She put the food in the solar cooker for heating and closed the lid. But she did not get good results. She then consulted her teacher to know her mistakes. Her teacher pointed out her mistakes, which she later rectified.
(a) According to you, which two mistakes were made by Mariyam and what did she do to rectify them?
(b) Which qualities of Mariyam are reflected in her action?   (CBSE 2014)
Answer:
(a) The box should be painted black as it absorbs more heat and it should be insulated from inside to prevent the loss of heat.
(b) The investigation skill and the right use of renewable source of energy.

Question 30.
Aditya suggests his family to install a solar water heater at their residence. But some of the family members were in favour of installing an electric geyser. Ultimately the family got water heater installed.
(a) Which according to you was correct? Give two reasons in support of your answer.
(b) Mention two possible changes in the thinking of the family members because of the arguments given by Aditya. (CBSE 2014)
Answer:
(a) The installation of solar water heater is a fair decision. This is because it will work on renewable source of energy and will cause no pollution.
(b) Two possible valid arguments of Aditya could be:
(i) An initiative to cut down the use of fossil fuels and use clean fuel.
(ii) The one-time installation of solar water heater will be more economical as it will cut down the heavy electricity bills in future.

Question 31.
(a) Name the four gases commonly present in bio-gas.
(b) List two advantages of using bio-gas over fossil fuels.  (CBSE 2015)
Answer:
(a) Four gases of bio-gas are methane (CH4), carbon dioxide, hydrogen and hydrogen sulphide. It contains 75% of methane.

(b) Two advantages of using bio-gas over fossil fuels are:

  1. It is renewable fuel, can be obtained again and again.
  2. It is cheap source of energy readily available for common man and the by¬product obtained can also be used as manure.

Question 32.
What are the disadvantages of constructing dams/producing electricity by hydro power plants?  (CBSE 2015)
(Or)
Why do people oppose the construction of Tehri Dam on the river Ganga and Sardar Sarovar project on the river Narmada?
(Or)
Mention three disadvantage of producing hydroelectricity by constructing the dams.
(Or)
List any three ways in which construction of dams for production of electricity adversely affects the environment of that place.  (CBSE 2015)
Answer:
Construction of dams has many disadvantages:

  1. Dams can be constructed in a limited number of places i.e., hilly terrains.
  2. Large area of agricultural land and human habitation get submerged. The eco-system gets disturbed.
  3. The vegetation which gets submerged, rots under anaerobic conditions and release methane gas which contributes to greenhouse effect.

Question 33.
Biogas is an excellent fuel. Justify the statement by giving two reasons. Mention the main constituents of biogas along with its percentage.  (CBSE 2015)
Answer:
(i) Four gases of bio-gas are methane (CH4), carbon dioxide, hydrogen and hydrogen sulphide. It contains 75% of methane.

(ii) Two advantages of using bio-gas over fossil fuels are:

  1. It is renewable fuel, can be obtained again and again.
  2. It is cheap source of energy readily available for common man and the by-product obtained can also be used as manure.
  3. It burns without smoke and leave no residue, therefore causes no atmospheric pollution.
  4. Its heating capacity is high, i.e., it has high calorific value.

Main constituents of biogas: The composition of biogas varies depending upon the nature of organic matter fed in the digester and advanced waste treatment technology. The typical composition of biogas is
Methane   50 – 75%
Carbon dioxide   25 – 50%
Nitrogen   0 – 10%
Hydrogen   0 – 1%
Hydrogen sulphide   0 – 3%

Question 34.
(a) Define tidal energy.
(b) Explain how the tidal energy is harnessed and write one limitation of the use of tidal energy. (CBSE 2015)
Answer:
(a) The energy produced by the movement of the ocean water during high tide and low tide creating a difference in the sea levels is called tidal energy. Due to the gravitational pull of moon the high tide and low tide is caused thereby causing tremendous movement of water which can be harnessed to produce electrical energy.

(b) A small dam is constructed at the site near the shore to collect the water that flows on the shore during the high tide, this water rotates the turbine and generates electricity.

Limitation: It is not a continuous process and occurs only during the time of high tide.

Question 35.
Define the process of nuclear fission. Write the steps involved in generating electricity in a nuclear reactor. (CBSE 2015)
Answer:
In nuclear power plants, a nuclear fuel is bombarded with projectiles which break the nucleus of radioactive substances like uranium, radium, polonium and it splits the big nucleus into two different atoms releasing large amount of heat energy. This heat energy can be controlled and used to produce steam. Large scale use of nuclear energy is prohibited because the nuclear fuel can be misused to make nuclear bomb. Its leakage can cause dangerous radio-active pollution.

Steps involved in generating electricity:

  • The fuel rods full of uranium pellets are placed in a nuclear reactor chamber.
  • Low-energy neutrons are bombarded on uranium fuel rod.
  • A self-sustaining fission chain reaction starts that releases energy at a controlled rate
  • With this heat the reactor converts water to steam at a high temperature and pressure.
  • This high temperature and pressure steam spins generator turbines producing electricity.
  • The steam cools back into water, which can then be used over again.

Source Of Energy Class 10 Important Questions Long Answer Type

Question 1.
Draw a labelled schematic diagram of a bio-gas plant. What use is made of the slurry left behind in the plant? (Foreign 2008)
Source Of Energy Class 10 Important Questions Science Chapter 14, 1
The spent slurry is used as manure.

Question 2.
Nikhil and Neha went to a remote village in Kerala to meet their grandmother. They were surprised to see a biogas plant in Mr. Nair’s house in the neighbourhood. There were plenty of livestocks and the household used cooking gas from the plant. Also their farms had rich vegetation. They contacted sarpanch of the village and convinced him to set up a biogas plant for village community.
(a) Mention the values displayed by Mr. Nair, Nikhil and Neha.
(b) Explain the possible arguments given by Nikhil and Neha to the sarpanch to convince him to set up community biogas plant.  (CBSE 2015)
Answer:
(a) Mr. Nair: Higher degree of general awareness, helping nature, environmental concern.
Nikhil and Neha: Knowledge sharing, helping nature and concern for community advantage.

(b) Possible arguments given by Nikhil and Neha in favour to set up community biogas plant, to the sarpanch are:

  • Economical source of energy
  • Cleanliness of the whole village.
  • Use of slurry left behind as manure which is rich in nitrogen and phosphorous.
  • Conservation of fossil fuels.
  • It reduces air pollution and greenhouse effect.
  • It raises the standard of living.
  • It is beneficial to entire village community. Basically they discuss and explain the advantages of community biogas plant for the entire village.

Question 3.
Solar cooker takes more time as compared to the LPG to boil potato or rice, yet Kunal use solar cooker for such type of cooking.
(a) Why does Kunal use Solar cooker instead of LPG? Give reasons for your answer.
(b) Name the phenomenon which is responsible for obtaining high temperature in solar cooker.  (CBSE 2015)
Answer:
(a) Solar cooker is cheap, uses solar energy. Hence economical and does not cause any pollution in the environment.
(b) Greenhouse effect.

Question 4.
Manoj’s father works in a nuclear power reactor. He asked his father to take him for a visit to nuclear power reactor. But his father was not keen to take him there. Now answer the following questions:
(a) What could be the possible reason of Manoj’s father not taking him to the nuclear power reactor?
(b) Write one advantage and one disadvantage of setting up a nuclear power reactor.   (CBSE 2015)
Answer:
(a)

  1. Safety concerns.
  2. Health concerns.

(b) Advantage: From a small amount of nuclear fuel, a large amount of energy is released in a nuclear power reactor.
Disadvantage: There is risk of harmful radiation leakage from nuclear waste.