Question

An object 3cm high is placed at a distance of 8cm from a concave mirror which produces avirtual image 4.5cm high

Answer 1

Concave mirror
h1 = +3 cm
h2 = -4.5 cm
u = -6 cm

m = h2 / h1
= -4.5 / +3
m = -3 / 2
-v / u = -3 / 2
Substituting u = -6 cm
We get v = -9 cm

1/f = 1/-9 + 1/-6
1/f = -15/54
f = 54/ -15
Simplifying
f = -18 / 5