Question

An object of size 4 cm placed perpendicular to
the principal axis of concave mirror at 12 cm from
the pole of the mirror. Find out the size of the
image if the radius of curvature is 20 cm.

Answer 1

Answer:

Focal length f=R/2=24/2=−12cm, using sign convention for concave mirror

Object distance u=−4cm

Image distance v=?

Using mirror formula

f

1

=

v

1

+

u

1

−12

1

=

v

1

+

−4

1

v

1

=

12

−1+3

v=+6cm

Hence.the position of image Is at 6cm behind the mirror.

Magnification(M)=

h

o

h

i

=

u

−v

=

−4

−6

=1.5>1

This shows that image is magnified.