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

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

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

An object is placed in front of concave mirror 20 cm away from it. If its focal length is 40 cm , locate the position of image and its nature.

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 ?

When an object is placed at a distance of 15 cm from a convex lens, a real image is formed at a distance of 30 cm. What is the focal length of the lens?