NCERT Solutions for Class 10 Science Chapter 14
NCERT Solutions for Class 10 Science Chapter 14 Sources of Energy intext questions on Page 243 or Page 248 or Page 253 or Page 254 and Exercises in English & Hindi Medium updated for new session 2020-2021.All the solutions are free to use online or download in PDF form. Question answers given on पेज 273 के उत्तर or पेज 279 के उत्तर or पेज 285 के उत्तर or पेज 286 के उत्तर or अभ्यास के उत्तर in Hindi study online or download in PDF format free. Download NCERT Books Solutions Apps 2020-21 based on Updated CBSE Syllabus for 2020-21.
NCERT Solutions for Class 10 Science Chapter 14
|Subject:||Science – Physics|
|Chapter 14:||Sources of Energy|
10th Science Chapter 14 Answers in English & Hindi Medium
10th Science Chapter 14 Answers in English Medium
10th Science Chapter 14 Answers in Hindi Medium
10th Science Chapter 14 Answers in PDF Form
What is geothermal energy?
The interior or deeper regions of earth’s crust are very hot. The temperature is so high that even rocks melts. If this heat is utilized as a source of energy, it is called geothermal energy.
Differentiate between renewable and non-renewable source of energy with one example for each.
(i) Non-renewable sources: Fossil fuels like coal, petroleum and natural gas are non-renewable energy sources. These are produced over millions of years due to slow changes and under special circumstances. These are not continuous processes and further it is not becoming possible to discover their new deposits. With the present rate of their consumption, it is estimated that known deposits of petroleum in our country will be exhausted in another 200 years and that of coal may last for another 250 years.
(ii) Renewable sources: The energy derived from flowing water, wind, tides, ocean waves and bio-gas are the renewable sources. These sources can be harnessed into energy so long as the earth derives its heat and light from the sun or so long as the present solar system exists. Nuclear energy and geothermal energy is also likely to be available for a much longer time. Wood is another renewable source of energy. Though it takes almost 15 years for a tree to mature, this and nuclear energy are also classified as renewable sources.
What are fossil fuels?
Coal, petroleum and natural gas are examples of fossil fuels. These are found in nature due to the decomposition of animals and plants which have remained embedded inside earth’s crust due to geological changes over millions of years.
What are wind energy farms?
The rotatory motion of the windmill can be utilized to rotate the armature of an electric generator in order to produce electricity. However, the electricity produced by a single windmill is quite small and thus cannot be used for commercial purpose. Therefore, a number of windmills are erected over a large area. The energy output of each windmill is coupled. This is called wind energy farms. The most essential condition for creating wind energy farms is to locate an area where wind blows for greater part of the year at a speed of about 15 km/h.
Questions for Practice
What is meant by a source of energy? OR What are the factors that should be taken into consideration for selecting a source of energy? List any three.
We need energy to perform various functions of life. The materials that provide the requisite amount of energy is the source of energy. For example,
(i) We need heat energy to cook food. The various sources are: Fuels, wood, coal, kerosene, cooking gas etc.
(ii) We need energy for our transport. The various sources are: petrol, diesel.
(iii) We need energy to light bulbs, tubes, to run radio, television and other power appliances. The source is electricity.
(iv) Production in factories and agriculture also need energy. The source is diesel and electricity.
What are the two disadvantages of burning fossil fuels? OR State with reason three disadvantages of using fossil fuels.
(i) Burning of coal and petroleum lead to air pollution.
(ii) They cause acid-rain by forming oxides of carbon, nitrogen and sulphur. This affects our water and soil sources.
(iii) Burning of fossil fuels cause smog which causes breathing problems and other hazards.
Questions from Board Papers
Why is bio-gas considered an ideal fuel for domestic use? OR Bio-gas is an excellent fuel. List three reasons to justify this statement.
Bio-gas is considered a good domestic fuel because of the following reasons:
(i) Bio-gas burns without any smoke and so does not cause air pollution.
(ii) Bio-gas produces a large amount of heat per unit mass and thus has high calorific value.
(iii) Bio-gas does not leave any residue on burning and is thus a clean fuel.
(iv) Bio-gas does not cause any storage problem. It can be continuously supplied by the pipes directly from the gas plant.
(v) The production of bio-gas does not involve any running cost and is cheaper than most common fuels.
Out of two solar cooker, one was covered by a plane glass slab and the other was left open. Which of the two solar cookers will be more effective and why?
The solar cooker covered with glass slab will be more efficient because the heat rays trapped in its will not be able to escape easily. Thus, the heating in this case will be better.
Important Questions on 10th Science Chapter 14
Disadvantage of a solar cooker is that it (solar cooker) is very expensive. It works only in sunlight. Hence, on cloudy day, it becomes useless.
The places where the days are too short or places with cloud covers round the year, have limited utility for solar cooker.
It is not possible to completely reduce the consumption of fossil fuels. However, some measures can be taken such as using electrical appliances wisely and not wasting electricity. Unnecessary usage of water should be avoided. Public transport system with mass transit must be adopted on a large scale. These small steps may help in reducing the consumption of natural resources and conserving them.
It should be easily available.
It should do a large amount of work (or produce large amount of heat) per unit volume/mass.
It should be easy to store and transport.
It should be economical.
It should cause less environmental pollution.
Burning of coal or petroleum causes air pollution.
Acidic oxides like oxides of carbon, nitrogen and sulphur are released on burning fossil fuels. These oxides lead to acid rains, which affect our water and soil resources.
Carbon dioxide gas also causes greenhouse effect in atmosphere.
Fossil fuels are non-renewable sources of energy.
Similarly, the wind energy is used to generate electricity. For the same purpose, the rotatory motion of windmill is used to tum the turbine of the electric generator.
There are very few locations where dams to utilise tidal energy can be built.
Cost of installation of power houses is extremely high and efficiency of plants is comparatively small.
Power plants built in oceans or at sea-shores will need high continuous maintenance as chances of corrosion are extremely high.
Large amount of energy is produced per unit mass.
It does not produce smoke. It is a clean energy.
Fission of one atom of uranium produces 10 million times the energy released by burning of one atom of carbon.
Fusion of four hydrogen atoms produces huge amount of energy.