An object of size 7.0 cm is placed at 27 cm in front of a concave mirror of focal length 18 cm. At what distance from the mirror should a screen be placed, so that a sharp focused image can be obtained? Find the size and the nature of the image.

Given that

u = – 27 cm

f = – 18 cm

h₀ = 7.0 cm

Find out

We need to find out size and nature of image

Formula

We know the mirror formula that

1/v = 1/f- 1/u

1/v = -1/18 + 1/27 = -1/54

V = – 54 cm

The screen must be placed at a distance of 54 cm from the mirror in front of it.

h_i/h₀= v/u

h_i/h₀= v/u

h_i/7 = +54/-27 h_i= -2 x 7 = -14 cm.

Thus, the image is of 14 cm length and is inverted image