Question
A vessel 20 cm deep is half-filled with oil of refractive index 1.37 and the other half is filled with water of refractive index 1.33. Find the apparent depth of the vessel when viewed from above.

Solution
The formula for apparent depth of the vessel is,
where,
Depth of the vessel, t = 20 cm,
Refractive index of oil, μ1 = 1.37 and
Refractive index of water, μ2 = 1.33
Substituting for t, μ1 and μ2, we get
Apparent depth, AD = 15.37 cm.
where,
Depth of the vessel, t = 20 cm,
Refractive index of oil, μ1 = 1.37 and
Refractive index of water, μ2 = 1.33
Substituting for t, μ1 and μ2, we get
Apparent depth, AD = 15.37 cm.