Class 10 Science - Chapter Sources of Energy NCERT Solutions | If you could use any source of energy fo

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?

What is a good source of energy?

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?

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

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?

Find out, from Table 10.3, the medium having highest optical density. Also find the medium with lowest optical density.

     Table 10.3 Absolute refractive index of some material media

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

What is the role of the acid in our stomach?

Describe the structure and functioning of nephrons.

What are the components of the transport system in human beings? What are the functions of these components?

How do auxins promote the growth of a tendril around a support?

Give an example of a double displacement reaction other than the one given in activity 1.10.

A Mendelian experiment consisted of breeding tall pea plants bearing violet flowers with short pea plants bearing white flowers. The progeny all bore violet flowers, but almost half of them were short. This suggests that the genetic make-up of the tall parent can be depicted as

(a) TTWW
(b) TTww
(c) TtWW
(d) TtWw

Why is the use of iodised salt advisable?

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

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