Question

A lens forms virtual image at a distance of 60 cm from a lens on right side If the lens is converging with focal length 40 cm then find object position

Answer 1

The distance of object from the lens is 120 cm  

Explanation:

Given as :

For a converging lens

The measure of focal lens = f = 40 cm

The distance of image from lens = v = 60 cm

Let The distance of object = u cm

According to question

From lens formula

∵    $\dfrac{1}{u}$  + $\dfrac{1}{v}$  = $\dfrac{1}{f}$

So,  $\dfrac{1}{u}$   = $\dfrac{1}{f}$  -  $\dfrac{1}{v}$

Or,  $\dfrac{1}{u}$   = $\dfrac{1}{40 cm}$  -  $\dfrac{1}{60cm}$

Or,  $\dfrac{1}{u}$   = $\dfrac{3-2}{120 cm}$

Or,  $\dfrac{1}{u}$   = $\dfrac{1}{120 cm}$

∴     u = 120 cm

So, The distance of object from the lens is 120 cm  . Answer

Answer 2

Explanation:

48 cm from left option c according to me