# Optical Physics

1. Sep 4, 2006

### feb2_sg

Given the wavelength of lightwave in a vacuum is 540mm, what will it be in water, where n = 1.33?

To solve this problem, it seems like I would need to find a relationship of the frequency of light to the wavelength and that is easily obtained from the equation lambda = c/nu and the frequency can be solved.

Since n=speed of light in vacuum/speed of light in material.

We can find the speed of light in the material (water) and thus the wavelength.

But it seems like there is a problem somewhere as I cannot seem to obtain a reasonable answer.

2. Sep 4, 2006

### Tomsk

You quoted the wavelength as 540mm, are you sure it's not nm? That would make sense if it's visible light. Then I'm pretty sure lambda(water)=lambda(vac)/n is right.

3. Sep 4, 2006

### feb2_sg

You know what. It is nm. I got an answer where the wavelength is 4.06*10^-7m. Anyone wants to double-check my answer?