Question

The wavelength of light in vacuum is 5000 A. When it travels normally through diamond the thickness of 1mm, what is the number of waves of lights in 1mm of diamond?

Answer 1

5000A is 500 nm and that is top end of blue… 

I mm = 1,000,000 nm

500nm into 1,000,000 = 2000 cycles, hertz, or wavelengths.

If there is any speed change or refraction I wouldn’t worry about it. 

It’s a pretty small diamond. :)