Question

The focal length of a concave mirror is 15 cm. The magnification of an object placed at a distance of 12 cm from the mirror is ?​

Answer 1

Answer: +5

Explanation:

object distance (u) = - 12cm

focal length (f) = - 15cm

Using Mirror Formula,

1/u + 1/v = 1/f

-1/12 + 1/v = - 1/15

1/v = -1/15 + 1/12 = -4+5/60 = + 1/60

v = +60cm

Magnification (m) = - v/u

= - 60/ -12 = +5

Hope it helps ❤️

Answer 2

Answer:

The magnification produced by the concave mirror is 5.

Explanation:

We will use the following relation to solve this question,

$m=\frac{f}{f-u}$     (1)

Where,

m=magnification of the mirror

f=focal length of the mirror

u=object distance from the mirror

From the question we have,

f=-15cm      (The focal length of the concave mirror is negative)

u=-12cm

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

$m=\frac{-15}{-15-(-12)}$

$m=\frac{-15}{-3}$

$m=5$

Hence, the magnification produced by the concave mirror is 5.