Question

a lens of focal length 12 cm produces a virtual image whose linear dimensions are 1/3 of the object. what is the distance of the object and image from the lens

Answer 1

Given:

The focal length of the lens f= 12 cm

The image is v=u/3

To find:

The distance of the object and image from the lens.

Solution:

The formula of lens is

1/f=1/v-1/u

Putting the above values

1/12=1/v-1/3v

Taking the LCM

1/12=3-1/3v

1/12=2/3v

v=8 cm

As u=3v

u=24 cm

So the distance of the object and image are 24 cm and 8 cm