When an object is placed 20 cm from a concave mirror, a real image magnified four times is formed. Find:

(a) the focal length of the mirror.

(b) Where must the object be placed to give a virtual image three times the height of the object?

An object 3 cm high is placed at a distance of 10 cm in front of a converging mirror of focal length 20 cm.

Find the position, nature and size of the image formed.

A concave mirror has a focal length of 4 cm and an object 2 cm tall is placed 9 cm away from it. Find the nature, position and size of the image formed.

A dentist's mirror has a radius of curvature of 3 cm. How far must it be placed from a small dental cavity to give a virtual image of the cavity that is magnified six times ?

A large concave mirror has a focus length of 0.75 cm. A person stands 10 m in front of the mirror. Where is the person's image ?