Question

A piano convex lens is made of refractive index 1.6. The radius of curvature of the curved surface is 60 cm. The focal length of the lens is

Options

• 50 cm

• 100 cm

• 200 cm

• 400 cm

Answer 1

100 cm

Explanation:

`1/f = (mu - 1) (1/R_1 - 1/R_2)`

= `(1.6 - 1) (1/oo - 1/(-60)) = 0.6/60`

`f` = 100 cm