Question

9. A 2.0-cm-high object is placed 12 cm from a convex
lens, perpendicular to its principal axis. The lens
forms a real image, whose size is 1.5 cm. Find the
power of the lens.​

Answer 1

Hi

As, there is convex lens .So, h=2cm,u=12cm,m=1.5cm.

As we know that ,m=v/u

1.5=v/12

1.5*12=v

18 cm=v

As we also know that 1/f=1/v-1/u

1/f=1/18-1/12

1/f= -1/36

f= -36

As, P =1/f

P =1/-36

P= -0.0277 D