Class 10 Science - Chapter Sources of Energy NCERT Solutions | What is a good source of 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?

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?

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

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?

What are alloys?

Make a diagram to show how hypermetropia is corrected. The near point of a hypermetropic eye is 1 m. What is the power of the lens required to correct this defect? Assume that the near point of the normal eye is 25 cm.

Give two important uses of washing soda and baking soda.

What are the advantages of sexual reproduction over asexual reproduction?

How does a solenoid behave like a magnet? Can you determine the north and south poles of a current–carrying solenoid with the help of a bar magnet? Explain.

How does our body respond when adrenaline is secreted into the blood?

Let the resistance of an electrical component remains constant while the potential difference across the two ends of the component decreases to half of its former value. What change will occur in the current through it?

Choose the correct option.

A rectangular coil of copper wires is rotated in a magnetic field. The direction of the induced current changes once in each

       (a) two revolutions         (b) one revolution
       (c) half revolution           (d) one-fourth revolution

Give any two ways in which non-biodegradable substances would affect the environment.

How do we detect the smell of an agarbatti (incense stick)?