You are asked to design a shaving mirror assuming that a person keeps it at 10 cm from his face and views the magnified image of the face at the closest comfortable distance of 25 cm . The radius of curvature of the mirror would then be:

Step-by-step solution

If A B is the position of the face of man then A ' B ' is the position of the image of a face. As the image is formed at 25   cm from the object. ∴ From concave mirror image is 15cm behind the mirror. So, u = - 10   c m ,   v =   + 15   c m ⇒ 1 f = 1 u + 1 v ⇒ 1 f = 1 - 10 + 1 15 = - 3 + 2 30 ⇒ f = - 30   cm . So, the radius of curvature, = 60   cm