Question

If the radius of curvature of a concave mirror is 20 cm, then its focal length is:

• A. 10

Answer 1

The correct option is A 10

Given,
Radius of curvature, $R=20cm$
We know
Focal length, $f=\frac{1}{2}\times R$
$=\frac{1}{2}\times 20$
$=10cm$