Question

A concave mirror has a focal length 30 cm. The distance between the two position of the object for which image size is double of the object is _________ . 

(A) 30 cm (B) 15 cm (C) – 25 cm (D) – 15 cm

Answer 1

The correct option is (A) 30 cm.

Explanation:

For real image, u = – u₁,

∴ distance between two positions = 45 – 15 = 30 cm.