Question

A beaker 20 cm high is half filled with an oil of refractive index 1.40 and the upper half filled with water of refractive index 1.33. What is the apparent depth of the beaker as observed normally?

Answer 1

Given:

Total height of beaker = 20 cm

Lower half: Oil, depth d₁ = 10 cm, n₁ = 1.40

Upper half: Water, depth d₂ = 10 cm, n₂ = 1.33

Formula:

Apparent depth = `d_1/n_1 + d_2/n_2`

= `10/1.40 + 10/1.33`

= 7.14 + 7.52

= 14.66 cm

The apparent depth of the beaker as observed normally is 14.66 cm.