Question

An object is placed at a distance of 40 cm from a concave mirror of focal length 15 cm. If the object is displaced through a distance of 20 cm towards the mirror, Find the displacement of the image.​

Answer 1

$\huge\pink{\boxed{Answer}}$

$v_1 \: =\: \frac{uf}{u-f}\:=\:\frac{-40\:×\:-15}{-40+15}\:=\:\frac{600}{-25}$

$\implies \:\-24\:cm$

$\huge\purple{\boxed{Second\:Case}}$

$v_2\:=\:\frac{uf}{u-f}\:=\:\frac{-20\:×\:-15}{-20\:+\:15}$

$\implies\:\-60\:cm$

$\huge\blue{\boxed{Displacement}}$

Displacement of the object = $v_2\:-\:v_1$

=> -60 - ( - 24 )

=> - 60 + 24

=> - 36 cm

So therefore we can conclude that the displacement of the object was - 36 CM away from the mirror