The focal length of a plano-concave lens is -10 cm , then its focal length when its palne surface is polished is

A plano-convex lens is made of flint glass, its focal length is

If the lens is double concave then its focal length is

A plano - convex lens is made of flint glass. Its focal length is

The focal length of a concave mirror is 10 cm. Find its radius of curvature.

Focal length of a glass lens in air is 2 cm. Its focal length when immersed in water would be:

Radius of curvature of plano-convex lens is 10 cm. If its focal length is 30 cm, then its refractive index will be .......