Question

A convex lens of focal length 8 cm forms a real image of the same size as the object. The distance between object and its image will be:

(a) 8 cm
(b) 16 cm
(c) 24 cm
(d) 32 cm

Answer 1

(d) 32 cm
A convex lens forms a real image at 2f on the right side of the lens. The size of the image is equal to that of the object if the object is placed at 2f.

∴ Distance between the image and the object = 2f + 2f = 4f = 4 $\times$ 8 = 32 cm