Question

A rod of length 10 cm lies along the principal axis of a concave mirror of focal length 10 cm in such away that the end closer to the pole is 20 cm away from it. Find the length of the image.

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