Question

A beam of light from a monochromatic laser shines into a piece of glass. The glass has thickness L and index of refraction n=1.5. The wavelength of the laser light in vacuum is L/10 and its frequency is f. In this problem, neither the constant c nor its numerical value should appear in any of your answers. How long does it take for a short pulse of light to travel from one end of the glass to the other? Express your answer in terms of the frequency, f. Use the numeric value given for n in the introduction.

Answer 1

`t = (15)/(f)`

Step-by-step explanation:

Light travels with the speed of light in a free space vacuum

In a piece of glass . the light travels at a speed
`v = (c)/(n)`

where ;

n = index of refraction

The time
`t = (L)/(v)`

where;

L = length of the glass slab

velocity
`v = (d)/(t)`

`t= (d)/(v)`

`t = (L)/((c)/(n)) \\\\t = \frac {n * L}{c}`

Also;
`c =\lambda f`

`t = (n*L)/(\lambda f)`

Given that;

wavelength
`\lambda = L/10`; and n = 1.5; we have:

`t = (n*L)/((L)/(10) f)`

`t = (10*n)/(f)`

`t = (10*1.5)/(f)`

`t = (15)/(f)`

Answer 2

Time taken = f/15

Step-by-step explanation:

Detailed explanation and calculation is shown in the image below