Double-convex lenses are to be manufactured from a glass of refractive index 1.55, with both faces of the same radius of curvature. What is the radius of curvature required if the focal length is to be 20cm?

A binoconves lens with both faces of the same radius of curvature is to be manufatured from a glass of refractive index 1.55.What should be the radius of curvature for the focal length of the lens to be 20 cm?

A plano-convex lens is made of refractive index 1.6.If the radius of curvature of the curved surface is 60 cm,then focal length of the lens is:

Find the focal length of convex mirror whose radius of curvature is 32 cm.

The radius of curvature of a spherical mirror is 20cm.What is its focal length?

The radius of curvature of a concave mirror is 30 cm what is its focal length?