Question

To a crane, a fish appears 6 cm below the water surface. Taking the refractive index of water as \[\frac{4}{3}\], the real depth of the fish below the surface is:

Options

• 6 cm

• 8 cm

• 9 cm

• 4.5 cm

Answer 1

Using \[n = \frac{\text{real depth}}{\text{apparent depth}}\] with \[n = \frac{4}{3}\] and apparent depth = 6 cm: \[\frac{4}{3} = \frac{R}{6} \Rightarrow R = 8 \text{ cm}\]. The fish is actually 8 cm below the surface, so the crane must immerse its beak 8 cm to reach it.