Question

A rod of length 12 cm is placed horizontally along the optical axis of a concave mirror of focal length 24 cm. The end near to the pole is at the centre of curvature. Find the length of image of rod.

Answer 1

Answer:

The position of image of nearer end to mirror can be found out using mirror equation,

v

1

+

u

1

=

f

1

⟹

v

1

1

=

−20

1

−

−10

1

⟹v

2

=−20

Similarly position of image of farther end to mirror can be found out as

=

v

2

1

=

−(10+20)

1

−

−10

1

⟹v

2

=−15

Hence the length of the image =20cm−15cm=5cm