A spherical mirror and a thin spherical lens have each a focal length of `- 15 cm`. The mirror and lens are likely to be

Options

A. both concave.
B. both convex.
C. the mirror is concave and the lens is convex.
D. the mirror is convex, but the lens is concave.

Answer

A

Explanation

As per the sign convention, the focal length of a concave mirror and a concave lens are taken as negative. Hence, both the spherical mirror and the thin spherical lens are concave in nature.