Question

If we say that the focal length of a spherical mirror is n times its radius of curvature, then n must be

• A. $1.5$
• B. $0.2$
• C. $2.0$
• D. none of these

Answer 1

The correct option is D

none of these

Explanation

A spherical mirror's focal length (f) is half its radius of curvature (R).

$f=\frac{R}{2}$

$\Rightarrow f=0.5R$

If the focal length is n times the radius of curvature, n must be $0.5$.

As a result, option (D) none of these are correct.