Please refer to below Exam Question for Class 10 Science Chapter 14 Sources of Energy These questions and answers have been prepared by expert Class 10 Science teachers based on the latest NCERT Book for Class 10 Science and examination guidelines issued by CBSE, NCERT, and KVS. We have provided Class 10 Science exam questions for all chapters in your textbooks. You will be able to easily learn problems and solutions which are expected to come in the upcoming class tests and exams for standard 10th.

Chapter 14 Sources of Energy Class 10 Science Exam Question

All questions and answers provided below for Exam Question Class 10 Science Chapter 14 Sources of Energy are very important and should be revised daily.

Exam Question Class 10 Science Chapter 14 Sources of Energy

ONE MARK QUESTIONS

Question: Name two fossil fuels.
Answer:
(i) LPG (ii) Coal

Question: Name two combustible components of biogas.
Answer: (i) Methane (ii) Hydrogen.

Question: Name four gases present in biogas.
Answer: a. Methane,
b. Hydrogen,
c. Hydrogen sulphide,
d. Carbon dioxide.

Question: Name the part of a biogas plant where reactions take place in absence of oxygen.
Answer: Digestor is part of biogas plant where reaction takes place in absence of oxygen.

Question: If energy can neither be created nor be destroyed, explain with an example why should we worry about our energy resources?
Answer: Energy remains conserved but energy lost to surrounding in less usable forms leads to energy crisis.
For example, electric bulb converts electric energy to useless heat energy besides light energy.

Question: Mention the purpose of blackening the interior of a solar cooker.
Answer: It is because black surface absorbs more (98%) heat as compared to white or reflecting surface or light coloured surfaces.

Question: Mention the minimum velocity of wind required for obtaining electric power with a wind mill generator.
Answer: 15 km/hour.

Question: Name the characteristic features of micro organisms which help in production of biogas in biogas plants.
Answer: The micro-organisms are anaerobic bacteria which break down organic matters and produce biogas in absence of oxygen (anaerobically).

Question: Name the major constituents of natural gas.
Answer: Methane is major constituent of natural gas.

Question: State the reason for calling fossil fuels as non-renewable source of energy.
Answer: These resources take millions of years in their formation, therefore, cannot be replaced, hence called non-renewable sources.

Question: List two steps of energy conversions in thermal power plants.
Answer: Chemical energy of fuel is converted into Heat energy.
Heat energy is used to produce steam which runs turbine and produce electricity (electric energy).

Question: Name a non-conventional renewable source of energy which can be harnessed for 24 hours throughout the year.
Answer: Geothermal energy is non-conventional source of energy which can be harnessed for 24 hours through out the year.

Question: A black surface absorbs more heat radiations as compared to a white or reflecting surface under identical conditions. List two solar devices which make use of this property in their design.
Answer: (i) Solar cooker, (ii) Solar water heater.

Question: What are hot spots inside earth’s crust?
Answer: The regions where molten rocks are formed in the deeper hot regions of earth crust which are pushed upward and trapped in certain regions called hot spots.

Question: List two forms of energy in which solar energy manifests itself in oceans.
Answer: (i) Ocean thermal energy, (ii) Tidal energy.

Question: What do you mean by fuel?
Answer: Fuel is a substance which produces heat and light on complete combustion.

Question: Mention the minimum temperature difference required between surface water and the water at depth of up to 2 km in an ocean thermal energy plant.
Answer:  20° C should be minimum difference in temperature.

Question: Why a solar cooker painted black from outside?
Answer: Black surface absorbs maximum solar energy (98%),that is why solar cooker is painted black from outside.

Question: Name any two characteristics which you look for in a good fuel.
Answer: a. It should have high calorific value.
b. It should not create pollution.

Question: Construction of dams submerges large areas of forests,
how does this contribute to the greenhouse effect?
Answer: Large eco-systems are destroyed when submerged under water in dams. The vegetation which is submerged rots under anaeboic conditions and give rise to large amounts of methane which causes greenhouse effect.

Question: Name the kind of energy possessed by wind and device used to harness it.
Answer: Kinetic energy is possessed by wind. Wind mill is the device which converts kinetic energy of wind into electrical energy.

Question: What is acid rain?
Answer: The rain water in which oxides of sulphur and nitrogen (acidic) get dissolved form acid rain.

Question: Name one fuel used in nuclear reactor.
Answer: Uranium is used as nuclear fuel.

Question: List two nutrients that the slurry left behind in the biogas plant contain.
Answer: a. Nitrogen
b. Phosphorus are present in slurry left in biogas plants.Question: Why solar cookers are to be covered with glass plate?
Answer: Solar cookers are covered with glass plate because it shows green house effect i.e., it traps solar radiations inside and does not allow to escape them to increase the temperature inside solar cooker.

Question: List two practical uses of biogas in rural areas.
Answer: (i) It is used as fuel.
(ii) It makes use of waste materials like animal dung into useful manure for crops.

Question: Write the name of the substance whose vapours are used to run the turbine of ocean thermal energy plant.
Answer: Ammonia vapours are used to run turbine of ocean

Question: Biogas is also known as gobar gas. Justify.
Answer: The main constituent of starting material for production of biogas is cow dung therefore, it is called ‘Gobar gas’.

Question: Name the reaction responsible for large energy production in the sun.
Answer: Nuclear fusion reaction is responsible for large energy produced in the Sun.

Question: How has the traditional use of wind energy been modified for our convenience. 
Answer: Rotatory motion of wind mill, with the help of wind energy is utilized to
(a) lift water from a well or
(b) turn the turbine of electric generator that generates electricity.

Question: Name the chief component of solar cells. What energy conversion takes place in solar cell?
Answer: Silicon is chief component of solar cell. It converts sunlight into electricity i.e., solar energy into electrical energy.

Question: How is nuclear energy generated during nuclear fusion?
Answer: Fusion means joining lighter nuclei to make a heavier nucleus most commonly, isotopes of hydrogen to create helium 

It releases tremendous amount of energy, according to  E=Δmc²
 where Δ m is called mass defect (difference in mass of reactants and products), c is velocity of light.

TWO MARKS QUESTIONS

Question: List the products of combustion of fossil fuels. State the harmful effects of products on environment.
Answer: Carbon dioxide and H₂O are main products of fossil fuels. Sulphur dioxide, oxides of nitrogen, carbon monoxide are also formed which create pollution,
(i) CO₂ causes greenhouse effect.
(ii) Oxides and sulphur and nitrogen cause acid rain.

Question: Briefly describe the working of thermal power plant.Why thermal power plants are set up near oil or coal fields?
Answer: Working of Thermal Power Plant :
a. Large amount of fossil fuels are burnt in thermal power plants .
b. Heat generated converts water into steam.
c. Steam runs turbine and generates electricity.
It is because transmission of electricity is more efficient than transporting coal or petroleum over the same distance. That is why thermal power plants are set up near coal or oil fields.

Question: Burning of fossil fuels is cause of global warming. Give reason in support of this statement.
Answer: Burning of fossil fuels produces carbon dioxide and water vapours which trap heat of sun radiations and increase the temperature of earth causing global warming. CO₂ is greenhouse gas.

Question: Define fuel. List any two characteristics that you would look for in a good fuel.
Answer: Fuel is a substance which produces heat as well as light on complete combustion.
Characteristics of good fuel :
a. It should be cheap and readily available.
b. It should not create pollution.

Question: Biogas is an excellent fuel. Justify the statement giving two reasons.
Answer: a. Biogas is clean fuel as it does not create pollution.
b. It makes use of waste materials and slurry left is used as a manure.

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 covered with plane glass slab will be more efficient. The glass lid allows the sunlight to enter the solar cooker but does not allow trapped radiation to go out of solar cooker. Trapped heat inside increases the temperature. Glass lid also reduces heat loss due to reflection.

Question: Out of elements A and B with mass number 2 and 235 respectively, which one is suitable for (i) fuel of a nuclear reactor (ii) making a hydrogen bomb. Name the nuclear reaction involved in each case. Write one difference between two types of reactions.
Answer: (i) U- 235 in used as a fuel in nuclear reactor.
(ii) Element with mass number 2 i.e., ?H is used in hydrogen bomb which is based on nuclear fusion reaction between isotopes of hydrogen to produce helium.
In nuclear reactor nuclear fission reaction takes place where as in hydrogen bomb nuclear fusion reaction takes place.
In nuclear fission heavy nuclei break into smaller nuclei whereas in nuclear fusion small nuclei combine to form bigger nuclei.

Question: Why is there a need to harness nonconventional sources of energy? Give two main reasons.
Answer: a. It is because non-conventional sources of energy are limited.
b. They create lot of pollution.

Question: A student constructed a box type solar cooker. He found that it did not work efficiently. Give any four possible mistakes in the construction and operation of the solar cooker. What maximum temperature can ordinarily be reached inside a solar cooker?
Answer: He may not have used or not properly oriented any of the following:
a. Black painted aluminium sheet to absorb heat radiation.
b. Glass sheet to prevent escape of heat.
c. Mirror plates that reflect sunlight to fall on the glass sheet.
d. Black cooking vessel to absorb more heat radiations.
e. The maximum temperature reached in solar cookers is around 100-140 °C,

Question: What is solar cell panel? Mention any three of its applications.
Answer: Solar cell panel: Solar cell panel ‘ is a panel on which large number of solar cells are connected together in a particular arrangement.Applications of solar panel:
a. It provides power for artificial satellites.b. It is used for running irrigation water pumps.
c. It also provides power for street lighting.

Question: What are the advantages of nuclear energy? 
Answer: A small amount of a fuel can generate large amount of energy. 1 atom of uranium produces 10 million times more energy than energy produced by 1 atom of carbon.

Question: Explain why:
(i) Solar cookers are covered with glass plate.
(ii) The solar cooker is painted black from inside.
Answer: (i) Glass plate does not allow heat to escape from solar cooker due to greenhouse effect.
(ii) Black colour absorbs maximum sunlight (98%).