Find the radius of curvature of a convex mirror whose focal length is 0.6 m.

The radius of curvature of a convex mirror is 24 cm.What is its focal length?(24 cm,6 cm,12 cm,3 cm)

Radius of curvature of a concave mirror is 24 cm. Then find the focal length of the mirror ?

Double-convex lenses are to be manufactured from by 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 of the lens is to be 20 cm ?