When curved surface of a plane convex lens is silvered then the focal power of the lense is

The convex surface of a plano-convex lens is silvered and the radius of curvature of this surface is R. Find the focal length of the system:

An object is placed 1m in front of the curved surface of a plano-convex lens whose plane surface is silvered. A real image is formed in front of the lens at a distance of 120cm. Then, the focal length of the lens is

The radii of curvature of both the surfaces of a convex lens are equal. One of the surfaces is made plane by grinding. What is the new focal power of the lens ?

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.

The effective focal length of the lens combination shown in Fig. is -60 cm . The radii of curvature of the curved surfaces of the plano-convex lenses are 12 cm each and refractive index of the material of the lens is 1.5 . The refractive index of the liquid is : .