Question
On a hot summer night, the refractive index of air is smallest near the ground and increases with height from the ground. When a light beam is directed horizontally, the Huygens’ principle leads us to conclude that as it travels, the light beam:
-
goes horizontally without any deflection
-
bends downwards
-
bends upwards
-
becomes narrower
Solution
D.
becomes narrower
According to Shell's law,
μ sinθ = constant
sin θ ∝ 1/μ
as μ increases, θ decreases.
