Question

A convex lens of focal length 12 cm produces a real image of magnification 2. The distance between object and its image formed by convex lens is​

Answer 1

SOLUTION :-

• please check the attached file

Answer 2

The distance between the object and the image formed is 54 cm.

Step-by-step Explanation:

Given: Focal length $f$ = 12 cm

magnification $m$ = -2 (negative sign for real image)

To Find: the distance between the object and the image formed

Solution:

• Finding the distance between the object and the image formed

The magnification $m$ is, $m = \frac{v}{u} = -2$ $\Rightarrow v = -2u$

And, the lens formula is

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

Substituting the given values in the above formula, we get;

$\Rightarrow \frac{1}{12} = \frac{1}{(-2u)} - \frac{1}{u} = -\frac{1}{u} (\frac{3}{2})$

$\Rightarrow u = -12 \times \frac{3}{2} = - 18 \ cm$

and, $v = -2u = 36 \ cm$

The distance between the object and the image is $v-u = 36+18=54 \ cm$

Hence, the distance between the object and the image formed is 54 cm.