Please help me find speed of light in flint glass

[jimbo43]

Homework Statement

A beam of light, wavelength 625 nm in air, is incident on a block of flint glass at an angle of 31.5.
Find:
A) the speed of light in the flint glass

Homework Equations

Don't know where to start

The Attempt at a Solution

refractive index of 1.61
625 / w = 1.61
w = 625 / 1.61 = 388 nm.

 

[G01]

You know the index of refraction of the medium. This should be all you need to find the speed in the glass.

HINT: How does the speed of light in a material relate to the speed of light in a vacuum and the index of refraction?

 

[Moetasim]

First, it is important to understand that the speed of light is a constant value and does not change based on the material it is passing through. However, the speed of light in a material can be affected by its refractive index, which is a measure of how much the speed of light is reduced when passing through that material.

To find the speed of light in flint glass, we can use the formula:

v = c / n

Where:
v = speed of light in the material
c = speed of light in a vacuum (approximately 3.00 x 10^8 m/s)
n = refractive index of the material

In this case, we are given the wavelength of light in air (625 nm) and the angle of incidence (31.5 degrees), but we need to find the refractive index of flint glass.

Using Snell's Law, we can find the refractive index:

n = sin(i) / sin(r)

Where:
i = angle of incidence (31.5 degrees)
r = angle of refraction (unknown, but can be solved for using Snell's Law)

Using the given information, we can solve for the angle of refraction:

sin(31.5) / sin(r) = 1.61
sin(r) = sin(31.5) / 1.61
r = sin^-1 (sin(31.5) / 1.61) = 19.6 degrees

Now, we have all the information we need to calculate the speed of light in flint glass:

v = (3.00 x 10^8 m/s) / 1.61 = 1.86 x 10^8 m/s

Therefore, the speed of light in flint glass is approximately 1.86 x 10^8 m/s.