Question

An object is placed at a distance of
40 cm from a concave mirror of focal
length 15 cm. If the object is displaced
through a distance of 20 cm towards
the mirror, the displacement of the
image will be

Answer 1

Explanation:

v/u = f/ f-u

v/40 =  -15 / -15 + 40

v =  -24cm

v / 20 = -15 / -15 +20

v =  -60cm

that is the mirror moved by 36 cm  away