Question

The radius of curvature of a spherical mirror is 20 cm. What is its focal length​

Answer 1

$\huge\text{Required\; solution}$

In the Question it is

Given -

• Radius of curvature of a spherical mirror = 20 cm (r)

Find -

• Focal length = ? (f)

Formula -

• Radius of curvature of the spherical mirror = 2 × focal length
• R = 2 × f
• R = 2f
• f = R/2

Putting values

• R = 20

→ f = R / 2

→ f = 20 / 2

→ f = 10 cm

hence the focal length of the given spherical mirror is 10 cm