Class 10 Science - Chapter Sources of Energy NCERT Solutions | What is geothermal energy?

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?

Hydrogen has been used as a rocket fuel. Would you consider it a cleaner fuel than CNG? Why or why not?

What are the disadvantages of fossil fuels?

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

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

Give the names of two energy sources that you would consider to be exhaustible. Give reasons for your choices.

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

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?

Why are coils of electric toasters and electric irons made of an alloy rather than a pure metal?

Why should we conserve forests and wildlife?

A shiny brown coloured element ‘X’ on heating in air becomes black in colour. Name the element ‘X’ and the black coloured compound formed.

How are involuntary actions and reflex actions different from each other?

What is the difference between the manner in which movement takes place in a sensitive plant and the movement in our legs?

Name two metals which are found in nature in the free state.

What are the advantages of connecting electrical devices in parallel with the battery instead of connecting them in series?

What are the differences between autotrophic nutrition and heterotrophic nutrition?

Why is sodium kept immersed in kerosene oil?

What are amphoteric oxides? Give two examples of amphoteric oxides.