Question

A concave mirror produces three times magnified image on a screen. If the object is placed
20 cm in front of the mirror, how far is the screen from the object ?​

Answer 1

here,

magnification,m= -3 (as the image is real)

object distance, u= -20 cm

image distance, v= ?

we know m= -v/u

-3= -(v/(-20))

v =-60cm

The screen is placed in front of the mirrorat a distance of 60cm from the pole of the mirror

Thus the screen is placed 40cm (=60-20cm) away from the object.