Question

7. A point light source is kept in front of a convex
mirror at a distance of 40 cm. The focal length
of the mirror is 40 cm. Find the position of
image.
Ans. Behind the mirror at a distance 20 cm

Answer 1

Answer:

$given \: \longrightarrow \\ u \: = - 40 \: cm \: \\ f \: = 40 \: cm$

$by \: mirror \: formula \: \\ \\ \frac{1}{f} = \frac{1}{v} + \frac{1}{u} \\ \\ \frac{1}{v} = \frac{1}{f} - \frac{1}{u} \\ \\ \: \: \: \: = \frac{1}{40} + \frac{1}{40} = \frac{2}{40} \\ \\ v \: = 20cm \: \\ since \: the \: value \: is\: positive \: the \: image \\ \: will \: be \: formed \: behind \: the \: mirror \: .$

Answer 2

Answer:

The image will be formed on the pole.

Explanation:

Referred to the attachment.