(a) Write the values of (i) angle of incidence, and (ii) angle of refraction.

(b) Use Snell’s law to find the refractive index of liquid with respect to air.

(a)

(i) The angle of incidence represents the angle made by the incident ray with the normal.

Therefore, ∠i = 90⁰ – 30⁰ 

∠i = 60⁰

(ii) Angle of refraction denotes the angle made by the refracted ray with the normal

Thus, ∠r = 90⁰ – 45⁰ 

∠r = 45⁰

(b) Using the Snell’s law, we can write

_air μ_liquid = sin i / sin r

_air μ_liquid = sin 60⁰ / sin 45⁰

_air μ_liquid = (√3 / 2) / (1 / √2) = (√3/2)

Therefore, _air μ_liquid = 1.22