Question

A double convex lens has a radii of curvature 1m and 2m what is th erefractive index if if focal length is 50 cm

Answer 1

Solution :-

As per the given data ,

• R 1 = 1 m = 100 cm

• R 2 = 2m = - 200 cm

• Focal length ( f) = 50 cm

We need to find the refractive index of the convex lens

Hence , by using the lens maker's formula ,

⇒ 1 / f = ( n - 1 ) ( 1 / R 1 - 1 / R 2 )

⇒ 1 / 50 = ( n - 1 ) ( 1 / 100 + 1 / 200 )

⇒ 1 / 50 = ( n - 1 ) ( 2 + 1 / 200 )

⇒ 1 / 50 = ( n - 1 ) ( 3 / 200 )

⇒ n - 1 = 200 / 50 x 3

⇒ n - 1 = 4 / 3

⇒ n - 1 = 1.33

⇒ n = 2.33

The refractive index of the biconvex lens is 2.33

Answer 2

Explanation:

using lense formula we can do this .answer is 2.33