CBSE Class 10 Science Sources of Energy VBQs

MCQ Questions for NCERT Class 10 Science Sources of Energy

Question. Which of the following gases is the main con-stituent of natural gas?
(a) Methane
(b) Ethane
(c) Propane
(d) Butane

Answer : A

Question. Wave energy is caused due to
(a) strong winds blowing across the sea
(b) kinetic energy possessed by huge waves near the sea shore
(c) potential energy possessed by the stored water
(d) both (a) and (b)

Answer : D

Question. The working fluid in ocean thermal power plant is
(a) Volatile liquid like ammonia
(b) petrol
(c) charcoal
(d) liquified petroleum gas

Answer : A

Question. The temperature inside the solar cooker ranges from
(a) 500-100°C
(b) 100-140°C
(c) 150-200°C
(d) 70-80°C

Answer : B

Question. U-235 will undergo fission by
(a) low energy neutrons only
(b) high energy neutrons only
(c) medium energy neutrons
(d) low energy protons only

Answer : D

Question. Biogas is a better fuel than animal dung cake because
(a) biogas has lower calorific value.
(b) animal dung cake has high calorific value
(c) biogas bums smoke and leaves no residue
(d) biogas is used as a fuel for cooking only wheareas dung cake can be used for cooking, illuminant the lanterns.

Answer : C

Question. One major problem in harnessing nuclear energy is
(a) converting nuclear energy into electrical energy.
(b) sustaining the reaction.
(e) splitting the nuclei.
(d) disposing off spent fuel easily.

Answer : D

Question. Which one of the following forms of energy leads to least environmental pollution in the process of its harnessing and utilisation? 
(a) Nuclear energy
(b) Thermal energy
(c) Solar energy
(d) Geothermal energy

Answer : C

Question. Fossile fuels are
(a) non-renewable source of energy
(b) renewable source of energy
(c) both (a) and (b)
(d) Neither (a) nor (b)

Answer : A

Question. Wind is caused due to
(a) uneven heating of earth’s surface
(b) rotation of earth
(c) local conditions
(d) All of these

Answer : D

Question. The power generated in a windmill 
(a) is more in rainy season since damp air would mean more air mass hitting the blades
(b) depends on the height of the tower
(c) depends on wind velocity
(d) can be increased by planting tall trees close to the tower

Answer : A

Question. Tidal energy is a farm of energy obtained from the
(a) motion of surface water in ponds
(b) ocean in the form of tidal waves
(c) tides occurs in the river water
(d) motion of the wave in sea

Answer : B

Question. The use of reflector in the solar cooker is to
(a) Decrease efficiency
(b) create green house effect
(c) increase efficiency
(d) none of these

Answer : C

Question. Geothermal energy is
(a) Heat energy in the interior of earth
(b) energy of molten mars exists in the farm of magma inside the earth.
(c) molten lava on the surface of earth
(d) energy obtained from solar thermal electric plants

Answer : C

Question. A good fuel should possess
(a) high ignition temperature
(b) moderate ignition temperature
(c) high calorific value
(d) both high calorific value and moderate ignition temperature

Answer : D

Question. An ideal source of energy should have
(a) higher calorific value
(b) easy transportability
(c) easy accessibility
(d) All of these

Answer : D

Question. Which of the following organism produces biogas from cow drug sherry in the biogas plant?
(a) aerobic bectria
(b) anaerobic bectria
(c) prolozoa
(d) fungi

Answer : B

Question. In a hydropower plant 
(a) Potential energy possessed by stored water is converted into electricity
(b) Kinetic energy possessed by stored water is converted into potential energy
(c) Electricity is extracted from water
(d) Water is converted into steam to produce electricity.

Answer : A

Question. Unit of calorific value of a substance is
(a) Kcal
(b) Joules
(c) J kg
(d) J/kg

Answer : D

Question. The major problem in harnessing nuclear energy is how to 
(a) split nuclei?
(b) sustain the reaction?
(c) dispose off spent fuel safely?
(d) convert nuclear energy into electrical energy?

Answer : C

Fill In the Blanks :

Question. Biogas is produced by the ………. of animal wastes or plant wastes in the presence of water.
Answer : anaerobic degradation

Question. Artificial satellites and space probes are electrified using ______________ .
Answer : Solar cells

Question. The energy produced during controlled ………. reactions is used for generating electricity at nuclear power plants.
Answer : nuclear fission

Question. A fuel is a good one if its ______________ value is high.
Answer : Butane

Question. Geothermal energy is widely trapped in USA and ______________ .
Answer : New Zealand

True/Fasle

Question. Nuclear fission reactions have been used to generate electricity.
Answer : True

Question. In order to fulfil our energy requirements, we try to improve the efficiency of energy requirements, we try to improve the efficiency of energy usage and also try and exploit new sources of energy.
Answer : True

Question. On an average, the 5.5 neutrons per fission is released.
Answer : True

Question. Sun is the ultimate source of energy.
Answer : True

Question. Wood is better fuel than charcoal.
Answer : False

Question. Bio-gas is a better fuel than animal dung-cakes.
Answer : True

Question. The main constituent of bio-gas is not methane.
Answer : False

Question. Charcoal is a better fuel than wood and coal.
Answer : True

Question. The use of geothermal energy cause pollution.
Answer : False

Question. Our energy requirements increase with our standard of living.
Answer : True

Assertion and Reason

DIRECTION : In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:

(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.
(e) Both Assertion and Reason are false.

Question. Assertion : Bio-gas is also known as Gobar gas.
Reason : The animal dung is the common material used in the bio-gas plant.
Answer : A

Question. Assertion : Solar cell is a device which converts solar energy i.e., light energy directly into electricity.
Reason : They are made up of semi-conductors likesilicon, germanium and selenium.
Answer : B

Question. Assertion : Wind energy is an environment friendly and efficient of energy.
Reason : Wind energy farms can be established everywhere.
Answer : C

Question. Assertion : Construction of big dams has lots of problems associated with them.
Reason : Large ecosystems are destroyed when submerged under the water in dams.
Answer : A

Question. Assertion : Solar cooker is painted white from inside.
Reason : The black surface to the solar cooker is a better heat absorber than a white surface.
Answer : D

Question. Assertion : Charcoal is a better fuel than wood.
Reason : It has a lower heat generation efficiency.
Answer : C

Question. Assertion : Solar energy, wind energy and hydro energy are considered to be exhaustible source of energy.
Reason : The rate of depletion of these energy sources, because of extraction of usable energy, is practically negligible.
Answer : D

Question. Assertion : U235 nucleus, by absorbing a slow neutron undergoes unclear fission with the evolution of a significant quantity of heat
Reason : During nuclear fission a part of the original mass of U235 is lost gets converted into heat.
Answer : A

Matching Questions

DIRECTION : Each question contains statements given in two columns which have to be matched. Statements (A, B, C, D) in column-I have to be matched with statements (p, q, r, s) in column II.

Question.

Answer : A-q, B-p, C-s, D-t, E-r, F-u, G-w, H-v

Question.

Answer : (d) A-p, B-q, C-r, D-s

Question.

Answer : (c) A-q, B-p, C-r, -D-s

Very Short Answer type Questions :

Question. Justify that the hydropower is a renewable source of energy.
Answer : Hydropower is generated from water flowing out of the dam and water in the reservoir would be refilled each time it rains through the high altitude rivers on which dam is constructed.

Question. A solar cell transforms energy of one form into another. What are these two ferm of energy?
Answer : A solar cell transform solar energy into electrical energy.

Question. Aspart from cow-dung, name other materials which can be used for making bio gas.
Answer : Various plant materials like the residue after harvesting the crops, vegetable waste and sewage.

Question. How does technology help in the transformation of energy?
Answer : Technologoy help us to provide the various means to transform the energy obtained from different source into useful form of energy.

Question. State the main difference between thermal power and hydropower plants based on electricity generation.
Answer : In thermal power plant, chemical energy of fossil fuel is used while potential energy of stored water is used in hydropower plant to produced electricity.

Question. Which country ranked first in harmessing wind energy for the production of electricity.
Answer : Germany.

Question. Why is CNG considered as environmental friendly fuel?
Answer : CNG does not produce any harmful gases on burning. So atmosphere does not gets polluted.

Question. Why a solar cooker painted black form outside? 
Answer : Black surface absorbs more heat as compared to white or reflecting surface under identical conditions.

Question. Name any two elements that are used in fabricating solar cells. 
Answer : Germanium, Silicon.

Question. Select the correct order of energy conversion in thermal power plant-
Answer : chemical energy – heat energy, mechanical energy, electrical energy

Question. Mention the minimum temperature difference required between surface water and water at a depth of upto 2 km in an ocean thermal energy plant.
Answer : 20 °C or 293 K in trapping geothermal energy

Question. Biogas is also known as gobar gas. Justify.
Answer : Starting material for biogas is mainly cow dung. So, it is also known as gobar gas.

Question. Name one fuel used in nuclear reactor.
Answer : Uranium-235.

Question. List two practical uses of biogas in rural areas.
Answer : Practical uses of biogas in rural area are:
1. It is an excellent fuel which burns without smoke with high heating capacity.
2. It is also used for lighting.

Question. Name any two elements that are used in fabricating solar cells.
Answer : Germanium, Silicon.

Question. Name any two fossil fuels.
Answer : A good fuel is the one which
• has high calorific value,
• is non-polluting,
• is easy to transport and easily available,
• has moderate ignition temperature.

Question. List two nutrients that the slurry left behind in the biogas plant contain.
Answer : Nitrogen and phosphorous.

Question. Name any two elements that are used in fabricating solar cells.
Answer : Germanium, Silicon.

Question. 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.
Answer : Solar cooker, solar water heater.

Short Answer type Questions :

Question. In the given flow chart of energy conversion during hydroelectric power generation,fill in the blanks with appropriate answer

Answer : Dynamo. 

Question. Consider two solar cooker, one covered with a plane glass plate and other kept open. Which of the two cooker would be more efficient and why?
Answer : Solar cooker with covered glass slab, as it will show green house effect. 

Question. Give one reason how increasing depandance on nuclear power generation is a threat for future generation?
Answer : Radiation emitted during leakage can change the genetic arrangement or disposal to nuclear waste. 

Question. Give two ways in which animal dung can be used as fuel. Which way is better and why?
Answer : As dung cake and as Biogas.. Biogas is better because it spreads less pollution and has more calorific value. 

Question. The wind velocity at three places A,B and C are 5Km/hr,15Km/hr,10Km/hr respectively. Which is the most suitable place for installing wind mill & why?
Answer : B, Maximum velocity required is 15km/h. At lower speed it will not work.
At very high speed it may break the blades. 

Question. What are two advantages of charcoal over wood as fuel?
Answer : High calorific value & pollution free 

Question.How difference in temperature helps to harness energy from ocean?
Answer : The difference in temperature helps to obtain energy in ocean- thermal – energy conservation plants, which operate for temperature difference of 20о C or more. The warm surface water is used to boil a volatile liquid . The vapours of the liquid are used to run the turbine of generator , the cold water from the depth of the ocean is pumped up and condense vapour again to liquid. 

Question. Mention any two reasons, why wood is not preferred as fuel.
Answer :(i) Burning wood causes pollution
(ii)Excess use of wood would cause deforestation. 

Question. Write three reasons why construction of Tehri Dam on river Ganga and Sardar Sarovar project on river Narmada is opposed by local people and environmentalist?
Answer : (i) Rehabilitation problems, loss of agricultural land.
(ii)Disturbance of ecological balance.
(iii) Forming of green house gases due to decomposition of plant in water. 

Question. Write three environmental consequences of the various source of energy we used?
Answer : Green house effect, improper use of natural resources, pollution.

Question. 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:
• working of artificial satellites stationed in outer space,
• running of irrigation water pumps by the farmers in rural areas,
• street lighting in remote areas.

Question. 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%

Question. (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:
a) It is an inexhaustible source of energy.
b) It does not cause any environmental pollution.
c) It is available at free of cost.

Question. 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.
Answer : It is not possible to make use of solar cells to meet all our energy needs because:
(i) of limited availability of special grade semiconducting materials such as silicon and germanium.
(ii) solar cells have lower efficiency as they depend entirely on intensity of solar radiation.
(iii) 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 of solar cells:
(i) They provide electric power to satellites and space probes.
(ii) They provide electric power to off-shore drilling platforms and light houses.
(iii) TV relay stations or wireless transmission systems located in remote areas use solar panels to get electric power.

Question. 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?
Answer : The solar cooker which was covered with a plane glass slab would be more efficient.
The glass lid allows the heat radiation from sun to enter the solar cooker but does not allow the reflected heat radiation to escape or go outside the box. Thus, heat trapped inside the box increases the temperature. Glass lid also reduces heat loss due to reflection.

Question. How are the wastes produced in nuclear power plants different from those produced in a thermal power plants ? What happens to the waste of a nuclear power plant?
Answer : The waste obtained from nuclear power plants is highly radioactive in nature which emits harmful radiations, whereas waste produced in a thermal power plant is non-radioactive. 
Management of nuclear waste is given as follows:
Some products of nuclear waste are buried in sealed steel/lead containers for a long term storage, buried under the ground or dumped in vacated coal mines.
Other waste products transforms into less harmful products or to products with a shorter half life.

Question. (a) How does construction of dams across the river get linked with production of greenhouse gases?
(b) How do technological inputs improve the efficiency of biomass fuels?
Answer : (a) A vast variety of plants get submerged in water, rot under anaerobic conditions and produce large amount of greenhouse gases such as methane.
(b) Traditional uses of biomass fuels are not only efficient but they also produce a lot of pollutants which are hazardous to health. Therefore, technological inputs are necessary to improve the efficiency of these fuels and make them environment friendly. With the help of technology, smokeless chulhas and biogas plants have been designed.

Question. Describe how hydro energy can be converted into electrical energy. Write any two limitations of hydro energy.
Answer : Conversion of hydro energy into electrical energy
• High rise dams are constructed on the river to obstruct the flow of water to collect it at a suitable height. The stored water has a lot of potential energy.
• The water from a suitable height is allowed to fall on the blades of a turbine located at the bottom of a dam through a pipe.
• Kinetic energy of flowing water rotates the turbine rapidly. Rotation of turbine helps the armature coil of generator to rotate rapidly in the magnetic field. Thus, hydroelectricity is generated.
Limitations of hydro energy:
(i) All river-sites are not suitable for construction of dams.
(ii) Large ecosystems are destroyed when submerged under the water in dam.

Question. Mention any four limitations in harnessing wind energy on a large scale.
Answer : Limitations in harnessing wind energy are:
a) Speed of wind is not available at all time and at all places.
b) To establish the wind energy farm, a large area of land is needed.
c) Speed of wind should be higher than 15 km/h to harness the wind energy.
d) Construction of windmill and its installation is very expensive.

Question. What happens when wood is burnt in a limited supply of oxygen? Name the residue left behind after the reaction and state two advantages of using this residue as a fuel over wood.
Answer : When wood is burnt in a limited supply of oxygen, volatile materials present in it get removed and cooled to get wood tar and wood gas.
The black residue left behind aftqr the reaction is known as charcoal. Advantages of using charcoal as a fuel over wood are:
Burning of charcoal does not produce smoke. On the other hand, wood produces a lot of smoke on burning.
For a given quantity, charcoal produces ,more heat than wood.

Question. (a) Charcoal is a better fuel than wood. Why? .
(b) How does biogas plant help to reduce the problem of pollution?
Answer : (a) Charcoal is considered to be a better fuel than wood because:
i) It burns without flames.
ii) It is comparatively smokeless.
iii) It has higher calorific value, i.e. higher heat generating efficiency than wood.
(b) Biogas plant helps to reduce the problem of pollution in the following ways.
i) It provides better sanitation due to safe disposal of bio-waste and sewage material.
ii) Biogas obtained from this plant produces less smoke on burning. (Hi) The residue left can be used as a manure which can be used as an alternative of fertilizers. Thus, it prevents soil and water from degradation.

Question. In a solar cooker, the following arrangements are made. Write one function of each arrangement.
(a) The box is made of insulating material such as plastic or wood.
(b) The inner walls of the box are painted black.
(c) The box is covered with a transparent glass sheet.
(d) A plane mirror is hinged at an angle at the top of the box.
Answer : (a) To avoid loss of heat from solar cooker to the surroundings.
(b) Black surface absorbs more heat radiations of incident energy.
(c) Transparent glass sheet does not allow the reflected heat radiation to go outside the box.
(d) To increase the amount of solar energy incident on the transparent glass sheet.

Question. Name four gases commonly present in biogas. State two advantages of using this gas over fossil fuels.
Answer : Methane, carbon dioxide, hydrogen and hydrogen sulphide. 
Advantages of using biogas over fossil fuels are:
Biogas burns without smoke, leaves no residue unlike coal.
Biogas is cheaper as compared to fossil fuels.