Question

An object is placed at a distance 24cm in front of a convex lens of focal length 8 cm.
Q. The distance of the image from the lens is ​

Answer 1

Explanation:

Given u=−24cm,f=+8cm,v=?

Using the lens formula

$\frac{1}{f} = \frac{1}{v} - \frac{1}{u} \\ </p><p>⇒</p><p></p><p> \frac{1}{v} = \frac{1}{f} + \frac{1}{u} \\ </p><p>$

$\frac{1}{v} = \frac{1}{8} + \frac{1}{( - 24) } \\ </p><p>⇒</p><p></p><p>v = + 12$

Answer 2

GIVEN :

Object distance from the lens  ( u ) = - 24 cm

Focal length of the lens ( f )= 8 cm

TO FIND :

The distance of the image from the lens(v)

SOLUTION :

Applying the len's formula,

             $\frac{1}{f} =\frac{1}{v} - \frac{1}{u}$

where f = focal length

          u = distance of the object from the lens

          v = distance of the image from the lens

        $\frac{1}{8} = \frac{1}{v} - \frac{1}{-24}$

here we taking u = -24 as the object is on the left side of the lens

 or,       $\frac{1}{v}$ =  $\frac{1}{8} - \frac{1}{24}$

 or,       $\frac{1}{v}$ = $\frac{3 - 1}{24}$

 or,       $\frac{1}{v}$ =  $\frac{2}{24}$

 or,       v =   12 cm.

∴ The distance of the image from the lens is 12 cm.