Question

An object is placed at a distance of 30 cm in front of a divergent lens, so that its image is formed 15 cm away from the lens. What is the power of the lens?​

Answer 1

u=-30cm

v=15

1/f=1/v-1/u

1/f=1/15+1/30

1/f=1/10

f=10

POWER OF LENS

D=1f

D=1×10

Power of lens = 10D