If the focal length of a spherical mirror is 12.5 less cm, its radius of curvature will be:(a) 25 cm (b) 15 cm (c) 20 cm (d) 35 cm

(a) 25 cm

Explanation

Given, 

Focal length = $f$ = 12.5 cm

To find = R = Radius of curvature

Solution

We know that,

Radius of curvature, $R = 2f$

Putting the given value we get-

$R = 2\times 12.5$

$R = 25 cm$

Hence, radius of curvature will be 25cm.