Question

Assertion : The resolving power of a telescope is more if the diameter of the objective lens is more.

Reason : Objective lenses of large diameter collected more light.

• A. If both, Assertion and Reason are true and the Reason is the correct explaination of the Assertion.
• B. If both, Assertion and Reason are true but Reason is not a correct explaination of the Assertion.
• C. If Assertion is true but the Reason is false.
• D. If both, Assertion and Reason are false

Answer 1

The correct option is B

If both, Assertion and Reason are true but Reason is not a correct explaination of the Assertion.

The explanation for the Assertion statement,

1. Resolving Power of telescope$=\frac{d}{1.22\lambda }$ (where, $d=$diameter of the objective lens, $\lambda =$wavelength)
2. Hence, the resolving power of a telescope is more if the diameter of the objective lens is more.

The explanation for the Reason statement,

1. The objective lens of a large diameter collects more light but does not increase the resolving power of the telescope because resolving power increases when angular separation increases.

Therefore both the Assertion and Reason are true but Reason is not a correct explanation for Assertion.

Hence, option (B) is true.