PHYSICS · Single correct · A Level · Physics · Waves · Waves
Problem
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:
(1) bends downwards
(2) bends upwards
(3) becomes narrower
(4) goes horizontally without any deflection