Question

1. Consider layers of three media of different index of refraction. The thickness of layers is the same, say L. Medium A has index of refraction 1.3; medium B has index of refraction 1.4 and medium C has index of refraction 1.35. Light enters these layers normally from the air. Rand these media in accordance the time it takes for light to travel through these layers, greatest first:

Answer 1

The thickness of these layer is same (equal to L), so the time taken to travel through each layer is given as--

t = (L / Vmed) here Vmed is the speed of light in that medium.

Now, if index of refraction is n, then by definition of n,

n = (Speed of light in vaccum) / (Speed of light in that medium)

So, it can be seen that greater the value of n, smaller is the speed of light in that medium, which implies that light takes takes more time to travel same thickness through that medium.

So, greater the value of n, greater is the time taken by light to travel through that medium.

So the order of time is:

  tB  > tC > tA