A light wave passing through a material has a frequency of 300 MHz and a wavelength of 0.15m. What is the index of refraction of the material?

Question

This is Physics 1. Please show your work and explain, cause I'm confused. Thanks!

Answer 1

Hi Nathalie,

First what you need to do is write out what you know from the problem:

frequency = 300 MHz = 300*10^6 Hz

wavelength = 0.15 m

Then, you write what you don't know and the equation you will use:

index of refraction = speed of light in vacuum/speed of light in medium

Next, we will write out any further equations. In this case, the speed of light in the medium and calculate it:

speed of light in medium = frequency x wavelength = 300,000,000*0.15 = 45,000,000 m/s

speed of light = 300,000,000 m/s (constant, we already know this)

index of refraction = speed of light in vacuum/speed of light in medium = 300,000,000/45,000,000 = 6.67

Hope this helps!