Question

A fish which is at a depth of 12 cm in water `(n = 4/3)` is viewed by an observer on the bank of a lake. The apparent depth as observed by the observer is ______.

Options

• 3 cm

• 9 cm

• 12 cm

• 16 cm

Answer 1

A fish which is at a depth of 12 cm in water `(n = 4/3)` is viewed by an observer on the bank of a lake. The apparent depth as observed by the observer is 9 cm.

Explanation:

Real depth = 12 cm, refractive index (n) = `4/3`

The relation between real depth (d) and apparent depth (d') is given by:

Apparent depth = `"Real depth"/n`

= `12/(4/3)`

= `12 xx 3/4`

= 9 cm

Hence, the observer sees the fish at an apparent depth of 9 cm.