Class 10 Science - Chapter Sources of Energy NCERT Solutions | Hydrogen has been used as a rocket fuel.

Can any source of energy be pollution-free? Why or why not?

What are the limitations of the energy that can be obtained from the oceans?

If you could use any source of energy for heating your food, which one would you use and why?

On what basis would you classify energy sources as

(a) renewable and non-renewable?
(b) exhaustible and inexhaustible?

Are the options given in (a) and (b) the same?

What is a good source of energy?

Which of the following is not an example of a bio-mass energy source?

      (a) wood                     (b) gobar-gas
      (c) nuclear energy      (d) coal

What are the disadvantages of fossil fuels?

Name two energy sources that you would consider to be renewable. Give reasons for your choices.

Compare and contrast fossil fuels and the Sun as direct sources of energy.

How has the traditional use of wind and water energy been modified for our convenience?

Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.

Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?

What are trophic levels? Give an example of a food chain and state the different trophic levels in it.

What changes can you make in your habits to become more environment-friendly?

What is the difference between a reflex action and walking?

What is the importance of DNA copying in reproduction?

If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?

Why should a magnesium ribbon be cleared before burning in air?

Define the principal focus of a concave mirror.

You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?

Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.

What does one mean by exothermic and endothermic reactions? Give examples.

A solution turns red litmus blue, its pH is likely to be

  (a) 1          (b) 4          (c) 5          (d) 10

Compare and contrast the arrangement of elements in Mendeléev’s Periodic Table and the Modern Periodic Table.

Which gas is usually liberated when an acid reacts with a metal? Illustrate with an example. How will you test for the presence of this gas?

Metallic oxides of zinc, magnesium and copper were heated with the following metals.

In which cases will you find displacement reactions taking place?

Why are carbon and its compounds used as fuels for most applications?

What is the role of the seminal vesicles and the prostate gland?

A mixture of oxygen and ethyne is burnt for welding. Can you tell why a mixture of ethyne and air is not used?

Why is sodium kept immersed in kerosene oil?