Question

If radius of curvature is 10 cm then focal lenth of convex lens is

Answer 1

Radius of curvature= (R)=10cm

Focal length=(f)=?

R=2f

10=2f

10/2=f

f=5cm

Answer 2

Answer:

Radius of Curvature

             The convex lens can be imagined as the part of two spheres.This spheres has a radius , it is known as the radius of curvature.

• focal length of the lens is half of its radius of curvature.

• 2(focal length) = Radius of curvature

• For a convex lens it is positive

• For a concave lens it is negative

Given:

• radius = 10cm

To find :

•   the focal length of the lens

Solution:

   2(focal length) = Radius of curvature

⇒ 2(focal length) = 10

⇒ focal length = 5cm

Therefore the focal length is 5cm