The focal length of plano-convex lens, the convex surface of which is silvered is `0.3m`, if `mu` of the lens is `7//4`, the radius of curvature of the convex surface is

A thin plano - convex lens acts like a concave mirror of focal length 0.2 m, when silvered on its plane surface. The refractive index of the material of the lens is 1.5. The radius of curvature of the convex surface of the lens will be

A thin plano-convex lens acts like a concave mirror of focal length 0.2m when silvered from its plane surface.The refractive index of the material of the lens is 1.5 .The radius of curvature of the convex surface of the lens will be: 0.1m

A thin plano-convex lens acts like a concave mirror of focal length 0.2 m when silvered from its plane surface. The refractive index of the material of the lens is 1.5. The radius of curvature of the convex surface of the lens will be

A plano-convex lens P and a concavo-convex lens Q are in contact as shown in figure. The refractive index o fthe material of the lens P and Q is 1.8 and 1.2 respectively. The radius of curvature of the concave surface of the lens Q is double the radius of curvature of the convex surface. The convex surface of Q is silvered.The focal lengthof combination is 8cm. The radius of curvature of common surface 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 1.5. The radius of curvature of its convex surface is R. Its focal length is

A plano-convex lens P and a concavo-convex lens Q are in contact as shown in figure. The refractive index o fthe material of the lens P and Q is 1.8 and 1.2 respectively. The radius of curvature of the concave surface of the lens Q is double the radius of curvature of the convex surface. The convex surface of Q is silvered. An object is placed on the placed on the principal axis at a distance 10 cm form the plane surface. The image is formed at a distance 40 cm from the plane surfaces on the same side. The focal length of the system is