Question

The following question contains two statements labeled ‘A’ and ‘R’. Examine each statement carefully and decide, if the assertion ‘A’ and reason ‘R’ are individually correct. If so, decide, whether the reason R is the correct explanation of A. Select your answer, using the options given below.

A : Stars twinkle, because a variable amount of light is received from them.

R : It is on account of atmospheric refraction.

• A. Both ‘A’ and ‘R’ are correct and ‘R’ is the correct explanation of ‘A’
• B. Both ‘A’ and ‘R’ are correct and ‘R’ is the not correct explanation of ‘A’
• C. ‘A’ is correct, but ‘R’ is incorrect.
• D. ‘A’ is incorrect, but ‘R’ is correct.

Answer 1

The correct option is A

Both ‘A’ and ‘R’ are correct and ‘R’ is the correct explanation of ‘A’

Explanation for assertion:

1. When the light rays from the stars reach our eyes, they pass through different layers of the atmosphere with variable optical densities.
2. This results in the bending of light rays due to refraction
3. Consequently, a variable amount of light reaches our eyes at different instants.
4. The combined effect of refraction at every instant makes the star twinkle.

Explanation for reason:

The bending of light rays while passing through the the atmospheric layers is called atmospheric refraction.

So the given assertion is true and the reason is the correct explanation of the assertion.

Hence, the correct option is A (Both ‘A’ and ‘R’ are correct and ‘R’ is the correct explanation of ‘A’)