The focal length of a plano-convex lens is `f` and its refractive index is 1.5 it is kept over a plane galss plate with its curved surface touching the glass plate. The gap between the lens and the glass plate is filled by a liquid. As a result the effective focal length of the combination becomes `2f`. Then the refractive index of the liquid is

A Plano-convex lens of radius of curvature 0.1m is kept over a plane glass plate with curved surface of the lens touching it. The gap between the glass plate and the curved surface of the lens is filled with a liquid. If the combined focal length of the combination is 0.4m, calculate the refractive index of the material of the liquid. Given R.I. of the material of the lens is 1.5.

A plano convex lens is made of glass of refractive index 1.5. The radius of curvature of its convex surface is R. Its focal length is

A plano convex lens is made of glass of refractive index 1.5. The radius of curvature of its convex surface is R. Its focal length is

A plano-convex lens is made of glass of refractive index 1.6. the radius of curvature of its curved surface is 30 cm. What is the focal length of the lens ?

The focal length of a glass convex lens of refractive index 1.5 is 20 cm. What is the focal power of the lens when immersed in a liquid of refractive index of 1.25 ?

The radius of curvature of curved surface of a thin plano-convex lens is 10 cm and the refractive index is 1.5 . If the plano surface is silvered, then the focal length will be.