Class 10 Science - Chapter Sources of Energy NCERT Solutions | Compare and contrast fossil fuels and th

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?

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?

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

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

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?

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

Give the names of two energy sources that you would consider to be exhaustible. 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?

How does chemical coordination take place in animals?

Explain the mechanism of the cleaning action of soaps.

You are given kerosene, turpentine and water. In which of these does the light travel fastest? Use the information given in Table 10.3.

Which of the following terms does not represent electrical power in a circuit?

(a) I²R          (b) IR²          (c) VI          (d) V²/R

Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.

One-half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object? Verify your answer experimentally. Explain your observations.

Why should curd and sour substances not be kept in brass and copper vessels?

The autotrophic mode of nutrition requires

         (a) carbon dioxide and water.         (c) sunlight.
         (b) chlorophyll.                                (d) all of the above.

What are the problems caused by the non-biodegradable wastes that we generate?

How does the embryo get nourishment inside the mother’s body?