Class 10 Science - Chapter Sources of Energy NCERT Solutions | How has the traditional use of wind and

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?

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

What is a good source of energy?

What are the disadvantages of fossil fuels?

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

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

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

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?

What is the function of digestive enzymes?

How are the areas of study – evolution and classification – interlinked?

Choose the correct option.

The magnetic field inside a long straight solenoid-carrying current

(a) is zero.
(b) decreases as we move towards its end.
(c) increases as we move towards its end.
(d) is the same at all points.

A student has difficulty reading the blackboard while sitting in the last row. What could be the defect the child is suffering from? How can it be corrected?

Name a device that helps to maintain a potential difference across a conductor.

A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 Ω resistance, which may be used separately, in series, or in parallel. What are the currents in the three cases?

Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?

What is a balanced chemical equation? Why should chemical equations be balanced?

How many structural isomers can you draw for pentane?