Question

Two statements are given one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer from the codes (A), (B), (C) and (D) as given below.
Assertion (A): In a reflecting telescope, the image does not have chromatic aberration.
Reason (R): Chromatic aberration occurs only due to refraction of light through an optical medium.

• A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
• B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
• C. Assertion (A) is true, but Reason (R) is false.
• D. Both Assertion (A) and Reason (R) are false.

Hint:

Chromatic aberration is caused by dispersion in lenses. Reflecting telescopes use mirrors — which don’t disperse light — so they avoid chromatic aberration completely.

Answer 1

The Correct Option is A

Assertion (A) is true: In a reflecting telescope, the image is formed using mirrors, and not lenses. Since mirrors reflect all wavelengths of light equally, there is no chromatic aberration. Reason (R) is also true: Chromatic aberration arises when different wavelengths of light are refracted (bent) by different amounts through a lens (optical medium), due to their varying refractive indices. Since reflecting telescopes use reflection (not refraction), they do not suffer from chromatic aberration. Therefore, the reason correctly explains the assertion.