Question

A concave mirror of focal length ‘f’ placed in a liquid then focal length of mirror becomes . The value of . A) More than ‘f’ B) Less than ‘f’ C) Same D) Data is insufficient​

Answer 1

Answer:

C) Same

Explanation:

When you keep any mirror inside a glass, the mirror may apear to be larger but the focus continues to be the focus irrespective of the media its kept under

Answer 2

Focal length of mirror remains same.

• Let's assume that the concave mirror has focal length f. It is inserted into a liquid of refractive index $\mu$.

First of all, let's define focal length:

• Focal length is the distance of pole from focus. In other words, it is half of RADIUS OF CURVATURE.

• Now, for any mirror, irrespective of the medium in which they are placed, the radius of curvature and the focal length remains constant.

• So, whether the mirror is kept in water or in oil, in both cases the focal length will be same.

Option C) is correct ✔️