Question

a converging mirror forms 3 times enlarged image of an object on a screen placed 30cm in front of it.find position of obj n radius of curvature

Answer 1

Given:
concave mirror:
m=3
v=-30cm
m=-v/u
u=-v/m
=30/3
=10cm

By mirror formula:
u=-10cm
v=-30
1/f=1/u+1/v
=-1/10-1/30
=-3-1/30
=-4/30
f=-30/4
=-7.5cm
R=2f=-15cm

Answer 2

Concave mirror :

m=3

v =-30cm

m=-v/u

u=-v/m

= 30/3

=10cm

By mirror formula :

u=-10cm

v=-30

1/f =1/u +1/v

= -1/10-1/30

= 3-1 /30

=-4/30

f= -30/4

= 7.5cm

R=2f= -15cm