Question

an object is placed at a distance of 12 cm from a concave mirror the image formed is real and four times larger than the object calculate the distance of the image from the mirror

Answer 1

Answer:

The distance of the image from the mirror is -48cm.

Explanation:

From the question we have,

The distance of the object from the mirror(u)=-12cm

The magnification(m) =-4           (∵The image formed is real)

And for magnification, we know that,

$m=\frac{-v}{u}$          (1)

Where,

m=magnification of the image

v=the distance of the image from the mirror

u=the distance of the object from the mirror

By substituting the value of m and u in equation (1) we get;

$-4=\frac{-v}{-12}$

$v=-4\times 12=-48cm$

Hence, the distance of the image from the mirror is -48cm.

Answer 2

Given,

the object is placed at a distance of 12 cm from a concave mirror the image formed is real and four times larger than the object

To find,

distance of the image from the mirror

Solution,

From the question, we know that

i. Distance of the object from the mirror = u = -12cm

ii. Magnification formed by the real image = m = -4

In physics, we know that

m = -v/u where,

m = magnification

v = distance of the image from the mirror

u = distance of the object from the mirror

Putting the values given to us in the equation, we get

- 4 = -v/-12

v = -4 x 12

v = -48cm

Hence, the distance of the image from the mirror is -48cm