# Refractive index of different colors

1. Feb 19, 2013

### MrEinstein

1. The problem statement, all variables and given/known data

I have to design an experiment to determine the difference in refractive indices for different colors.

Assume you have : color filters,glass block

2. Relevant equations

3. The attempt at a solution

I want to do it buy shining a white laser light through filters into the glass block and measuring the angle of incidence and refraction using a protractor. But they say to take into account the fact that the variation of refractive index with frequency is very small. So what else can I do to take that into account?

2. Feb 19, 2013

### Staff: Mentor

Total reflection might be interesting to study, as it is quite sensitive to small angle differences.
A prism would be easier, of course.

3. Feb 19, 2013

### MrEinstein

But what exactly do we use to measure the angle of refraction? It's going to be such a small angle difference that a protractor can't help. Yeah,with a prism it would be easy but they say that you have a rectangular glass block so they clearly want you to use it.

4. Feb 19, 2013

### Staff: Mentor

Measure the position of the beam at different points and use trigonometry? If you just need the difference and not an absolute value, it is easier.

5. Feb 19, 2013

### MrEinstein

Ahhh trigs. Length can be measured more accurately than angles. This explains the glass block, instant right angled triangle.
Thank you man