Question

The focal length of a concave mirror in air is f. When the mirror is immersed in a liquid of refractive index `5/3`, its focal length will become ______.

Options

• `5/3` f

• `3/5` f

• `2/3` f

• f

Answer 1

The focal length of a concave mirror in air is f. When the mirror is immersed in a liquid of refractive index `5/3`, its focal length will become f.

Explanation:

Because the mirror reflection follows to the rules of reflection, which are constant regardless of the medium, the focal length of a concave mirror is independent of the surrounding medium's refractive index.