Question

Light travels through a glass plate of thickness t and having refractive index μ. If c be the velocity of light in vacuum, the time taken by the light to travel this thickness of glass is(a) $\frac{t}{\mu c}$(b) tμc(c) $\frac{\mu t}{c}$(d) $\frac{tc}{\mu}$

Answer 1

Answer:

C)  ut/c

Explanation:

Light travels fastest at a speed of c m/s in vacuum and slows down in other denser media depending upon the refractive index of the denser media. Here we have glass as a dense medium whose refractive index is n. Thus,

Speed of light in glass plate = c/u

Because,  v = Speed of light in vacuum/ R.I of the medium

Time taken = t/c = ut/c

where t is the thickness of the glass plate.

Thus, time taken by the light to travel this thickness of glass is ut/c