Question

Which of the following relations hold good for 'R' and 'F', where 'R' is the radius of curvature of a spherical mirror and 'F' is the focal length of the mirror?

• A. R = F
• B. $R=\frac{F}{2}$
• C. $F=\frac{R}{2}$
• D. 2F = R

Answer 1

Answer: (C), (D)

The correct options are
C

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

D

2F = R

The focal point occurs at the midpoint between pole and radius of curvature. So, if radius of curvature is $R$ and focus is $F$, then, $F=\frac{R}{2}$ or $2F=R$.