Question

An object is placed near a concave mirror having a radius of curvature of magnitude 60 cm. How far should you place the object from the mirror so that the lateral magnification produced by the mirror will be 2.5?

Answer 1

Answer:

u = 18 cm

Explanation:

given,

radius of curvature = 60 cm

magnification of mirror = 2.5

distance of object  = ?

R = 2 f

f = R/2

f = 60/2 = 30 cm

$m = -\dfrac{v}{u}$

$2.5 = -\dfrac{v}{u}$

v = -2.5 u

now,

Using mirror formula

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

$\dfrac{1}{30} = \dfrac{1}{-2.5u} + \dfrac{1}{u}$

$\dfrac{1}{30} = \dfrac{0.6}{u}$

u = 0.6 x 30

u = 18 cm

distance of object be equal to u = 18 cm