Question

The radius of curvature of a spherical mirror is 90cm. What is its focal length ?​

Answer 1

Answer:

Hence, the focal length of the given spherical mirror is 45cm.

Explanation:

We have-

Radius of curvature,

R = 90 cm

Radius of curvature of a spherical mirror

= > 2 x focal length(f)

=> R = 2f

=> f = R/2

=> f = 90/2

=> f = 45cm.

Hence, the focal length of the given spherical mirror is 45cm.

Answer 2

Explanation:

$Focal \: length \: = \: \frac{Radius \: of \: curvature}{2} \\ or \: f = \frac{r}{2} \\ \\ f \: = \: \frac{90}{2} \\ \\ f = 45cm \\ \\ Thus, \: the \: focal \: length \: of \: convex \: mirror \: is \: 45cm.$