Please refer to Assignments Class 10 Science Sources of Energy Chapter 14 with solved questions and answers. We have provided Class 10 Science Assignments for all chapters on our website. These problems and solutions for Chapter 14 Sources of Energy Class 10 Science have been prepared as per the latest syllabus and books issued for the current academic year. Learn these solved important questions to get more marks in your class tests and examinations.
Sources of Energy Assignments Class 10 Science
Question. Mention any four limitations in harnessing wind energy on a large scale.
Answer: Limitations in harnessing wind energy on a large scale are :
(i) Wind energy farms can be established only where the minimum velocity of wind is 15 km/h.
(ii) The kinetic energy of wind can be used only at the site of a windmill.
(iii) Wind energy cannot be used to operate all types of machines.
(iv) It is expensive to set up a wind farm for generating electricity because wind farms need a large area.
Question. (a) Distinguish between renewable and nonrenewable sources of energy.
(b) Choose the renewable sources of energy from the following list : coal, biogas, sun, natural gas
(b) Sun is a renewable source of energy.
Question. Define :
(ii) Anaerobic degradation
Answer: (i) Biomass : Cow-dung, various plant materials like the residue aft er harvesting the crops, vegetable wastes and sewage which can be decomposed in the absence of oxygen is called biomass.
(ii) Anaerobic degradation : Breaking of large organic molecules into simple molecules in the absence of air is called anaerobic degradation.
Question. Write two advantages of classifying energy sources as renewable and non-renewable.
Answer: The two advantages of classifying energy sources as renewable and non-renewable are:
(i) Increasing use of renewable energy sources rather then using non-reversible sources of energy.
(ii) A judicious use of non-renewable energy source so as to prevent its depletion.
Question. While discussing about coal and petroleum, a teacher told his students about PCRA’s (Petroleum Conservation Research Association) guidelines to save the fossil fuels while driving vehicles. Deepa was going to her school with her mother who was driving car. At the traffic signal, when the light was red, Deepa suggested her mother to switch of the engine.
After reading the above passage, answer the following questions :
(a) Fossil fuels are natural resources, then why do we need to conserve them?
(b) List any two ways of saving the fossil fuels.
(c) State two values exhibited by Deepa.
Answer: (a) Fossil fuels are natural resources but they are non-renewable and exhaustible. Also, it takes millions of years for their formation. So they must be conserved to provide energy for longer duration and for sustainable development.
(b) (i) Using public transport and walking for short distances.
(ii) Using solar energy over conventional sources of energy.
(c) Deepa is concerned about natural resources and environment and assertive in nature.
Question. List any four disadvantages of using fossil fuels for the production of energy.
Answer: Disadvantages of using fossil fuels for the production of energy are :
(i) Fossil fuels are non-renewable source of energy.
(ii) It causes air pollution to the environment.
(iii) It takes millions of years for its formation.
(iv) It causes acid rain.
Question. What are fossil fuels? “Burning fossil fuels may lead to intense global warming.”
Answer: Fossil fuels : The combustible substances formed from the dead remains of the animals and plants which were buried deep under the surface of the earth for over millions of years are called fossil fuels.
Burning of fossil fuels produces carbon dioxide and excess carbon dioxide in the atmosphere causes the greenhouse effect, leading to intense global warming.
Question. How is the increase demand for energy affecting our environment adversely?
Answer: Environmental consequences of the increasing demand for energy are the following:
(i) Burning of fossil fuels increases the amount of carbon dioxide in the atmosphere which leads to global warming.
(ii) Deforestation for obtaining firewood causes soil erosion and destruction of wildlife.
(iii) Construction of dams to generate hydroelectric power destroys large ecosystems which get submerged under water.
(iv) Nuclear power plants increases nuclear radiation in the environment.
Question. What is the importance of hydropower plants in India? Describe how electric energy is generated in such plants.
Answer: Importance of hydropower plants in India :
(i) Hydropower plants fulill 25% of energy requirement in India.
(ii) Since it is powered by water which is a renewable resource, hydropower plants can run throughout the year.
(iii) It is very economical to produce electricity by hydropower plants.
(iv) As the electrical energy is harnessed by the flow of water, it does not cause pollution.
Production of electrical energy from hydropower plants In order to produce electricity, high-rise dams are constructed on a river to obstruct the flow of water and thereby water gets collected in a large reservoir. A dam helps to generate electricity by releasing a controlled flow of water at high pressure through a gate called penstock from a reservoir.
Here, it spins the turbines which turns the turbines of the generator, producing electric current. The electricity generated from the hydropower plant is transmitted to consumers through high voltage power lines.
Question. What is biogas? Why is biogas considered as an ideal fuel for domestic use?
Answer: Gas which is produced by the decomposition of cow-dung and various plant materials in the absence of oxygen is called biogas. Biogas is considered as an ideal fuel because
(i) it does not produce smoke
(ii) its heating capacity is high
(iii) slurry left behind can be used as an excellent manure.
Question. Give two examples each of the following :
(i) Renewable sources of energy
(ii) Non-renewable sources of energy
Answer: (i) Examples of renewable sources of energy are wind energy, solar energy, etc.
(ii) Coal, petroleum and natural gas are two examples of non-renewable sources of energy.
Question. Draw a labelled schematic diagram of a biogas plant. What use is made of the slurry left behind in biogas plants?
The slurry left behind in biogas plant can be used as manure which works as an organic fertilizer.
Question. List any four limitations of the energy obtained from oceans.
Answer: Limitations of the energy obtained from ocean are:
(i) Ocean thermal energy can only be utilise at the places located at coastal areas.
(ii) Electricity produced from this energy is very less.
(iii) Ocean thermal energy can only be utilised if the temperature difference between the water at the surface and water at depth upto 2 km is 20°C.
(iv) Utilisation of this energy is limited only during day time with sufficient sunlight.
Question. What is the main constituent of biogas? How is biogas obtained from biomass? Write any two advantages of using this gas.
Answer: The main constituent of biogas is methane (75%). Biogas is obtained by anaerobic decomposition of biomass in biogas plant. The two advantages of using this gas are
(i) It does not produce smoke.
(ii) It has high caloriffic value.
Question. Firewood is our conventional fuel. List any four reasons for replacing it by the alternate sources of energy.
Answer: Firewood is our conventional fuel. It should be replaced by alternate sources of energy due to following reasons:
(i) It produces less heat on burning.
(ii) It produces lots of smoke.
(iii) Cutting down of trees causes depletion of forest leading to imbalance in nature.
(iv) Due to low caloriffic value of wood it requires a large quantity of wood to generate a sufficient amount of heat.