Class 10 Science - Chapter Sources of Energy NCERT Solutions | Can any source of energy be pollution-fr

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?

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.

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

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

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?

List two methods of producing magnetic fields.

What is hydrogenation? What is its industrial application?

Can the wing of a butterfly and the wing of a bat be considered homologous organs? Why or why not?

The values of current I flowing in a given resistor for the corresponding values of potential difference V across the resistor are given below –

I (amperes)   0.5   1.0   2.0   3.0    4.0
V (volts)        1.6   3.4   6.7   10.2  13.2

Plot a graph between V and I and calculate the resistance of that resistor.

Name the substance which on treatment with chlorine yields bleaching powder.

Draw the electron dot structures for

(a) ethanoic acid.
(b) H₂S.
(c) propanone.
(d) F₂.

Five solutions A,B,C,D and E when tested with universal indicator showed pH as 4,1,11,7 and 9, respectively. Which solution is

(a) neutral?
(b) strongly alkaline?
(c) strongly acidic?
(d) weakly acidic?
(e) weakly alkaline?

Arrange the pH in increasing order of hydrogen-ion concentration.

Name a mirror that can give an erect and enlarged image of an object.

What are plant hormones?

Define the principal focus of a concave mirror.