Some modern optical devices are made with glass whose index of refraction changes with distance from the

Question:

Some modern optical devices are made with glass whose index of refraction changes with distance from the front surface. FIGURE CP16.84 shows the index of refraction as a function of the distance into a slab of glass of thickness L.
The index of refraction increases linearly from n₁at the front surface to n₂at the rear surface.
a. Find an expression for the time light takes to travel through this piece of glass.
b. Evaluate your expression for a 1.0-cm-thick piece of glass for which n₁= 1.50 and n₂= 1.60.

$Index of refraction n П2 п Distance FIGURE CP16.84$