Question

Convergence of concave mirror can be decreased by dipping in
(A) Water
(B) Oil
(C) Both
(D) None of these

Answer 1

A concave mirror is used for converging the light reflecting on it. The structure of a concave mirror is made in such a way that it curves inside, which means that the mirror is curved in such a way that it reflects the light towards the inside to a single focus point. The main application of a concave mirror is as a converging device or a point reflector in a solar plate.

Complete step by step solution:
As we know that the mirrors are used to reflect the light incident upon them. The laws of reflection are as follows-
(1) The angle of incident rays of light is equal to the reflected ray of light. So, the angle of incidence is equal to the angle of reflection of light.
(2) The reflected ray, the incident ray and the normal at the point of incident ray all of them lie in the same plane.
Now from these laws of reflection, it is clear that for the reflection of the light, the mirror is unaffected by the effects of dipping. Also, the refraction of the light is not possible in this case so we can say that convergence of a concave mirror is unaffected by any medium.
Therefore, the correct option is (D).

Note:
The refraction occurs when the light passes through multiple mediums, but as we know that the application of a mirror does not involve any refraction, it only involves reflection. So, we can say that there is no effect in the working of a mirror by dipping a mirror into any medium.