Question

Find the focal length of a convex mirror whose radius of curvature is 32cm ?

Answer 1

Provided that:

• Convex mirror is given.
• Radius of curvature = +32 cm

To calculate:

• The focal length

Solution:

• The focal length = 16 cm

Using concept

• Focal length formula

Using formula:

• f = R/2

Where, f denotes focal length and R denotes radius of curvature.

Knowledge required:

• In a convex mirror focal length is always positive.

• In a convex mirror radius of curvature is always positive.

Required solution:

»»» f = R/2

»»» f = 32/2

»»» f = 16 cm

»»» Focal length = 16 cm $\:$

Answer 2

Answer:

The focal length of spherical mirrors are half its radius of curvature.

so, 2f = R

or f = R/2 = 32/2 = 16

So, focal length of a convex mirror whose radius of curvature is 16cm.

As it is convex mirror, by sign convention, it is (+16) cm