Question

A concave mirror produces a real image of size 3 times that of the object at a distance of 30cm from the pole of the mirror.find the position of the object

Answer 1

Given:
Object distance =u=-30cm(by sign convention)
v=?
height of object be =h cm
height of image=- 3h cm(real image)h=-v/u

m=height of image/height of object
⇒-3h/h = -v/u
h3=v/u
⇒v=uX3
∵u=-30cm
we get v=-30x3
⇒-90cm
Negative sign indicates that image formed is real and inverted at a distance of 90cm from mirror.

Answer 2

u =-30

V=?

h'=3h

m=h'/h

=3h/h

=3

m=-v/u

3=-v/-30=

-90=-v

V=90