Question

A beam of light is incident on a flat air-liquid interface at an angle if incidence 52.0◦ and is
observed to travel inside the liquid at an angle of 49.0◦

with the interface. The refractive index of

the liquid is:
A. 1.90
B. 1.50
C. 1.40
D. 1.20
E. None of the above.

Answer 1

Refractive index of air = n₁ = 1.0003

Refractive index of the liquid = n₂

Angle of incidence (angle the light beam makes with the normal in air) = ₁ = 52^o

Angle the beam of light makes inside the liquid with the interface = = 49^o

Angle of refraction (angle the light beam makes with the normal in the liquid) = ₂

₂ = 90 -

₂ = 90 - 49

₂ = 41^o

By Snell's Law,

n₂ = 1.20

Refractive index of the liquid = 1.20