The diagram above shows an incident ray A, inclined at angle of 50º to the interface CB. The ray OB is found to lie along the surface. What is the refractive index of the medium X with respect to air?
The correct answer is: D
Explanation
angle of incidence = 90º - 50º = 40º
the angle the refracted ray makes with the normal is 90º
but refractive index(n) = \(\frac{i}{r} = \frac{40}{90}\).