Rays from sun converge at a point 15 cm in front of a concave mirror. Where should an object be placed so that size of the image is exactly equal to the size of the object ?

Rays from sun converge at a point 15 cm in front of a concave mirror.

1.	Rays from sun converge at a point 15 cm in front of a concave mirror. Where should an object be placed so that size of the image is exactly equal to the size of the object ?
Answer» 30 cm in front of mirror 15 cm in front of mirror between 15 cm and 30 cm in front of mirror Less than 15 cm in front of mirror Solution :As light rays from sun `(u = oo)` converge at a point 15 cm in front of a concave mirror, hence focal LENGTH of concave mirror f = - 15 cm. To FORM an IMAGE of exactly same size as that of an object, the object should be placed at the CENTRE of curvature (u = R = 2f) of mirror. Hence, the object should be placed at 30 cm in front of mirror.