# Homework Help: Total internal reflection

1. Apr 6, 2009

### aimslin22

1. The problem statement, all variables and given/known data
The prism is replaced by a new prism of the same shape, which is set in the same position. The light beam experiences total internal reflection at the right surface of this prism. What is the minimum possible index of refraction of this prism?

2. Relevant equations
Snell's law

nsinx=nsinx

3. The attempt at a solution
I think know how to do it, I just need to know what "total internal reflection" means. Please help
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Apr 6, 2009

### DrMon

Total internal reflection is what occurs when the light hits a medium boundry at such a wide angle the the light completely 'bounces' off the boundry, without crossing it.
For example, if the light hits a boundry of a perspex prism and air - and bounces back into the prism instead of proceeding out into the air.
If I remember correctly, the angle is hits the boundry at is the angle is bounces back at.

3. Apr 6, 2009

### aimslin22

...so the angles in Snell's law would be the same?

4. Apr 6, 2009

### DrMon

Well I'm not sure - Because you only seem to have a fragment of the question there which refers to other sections of the question.
However, since you said you only needed to know what total internal reflection is - and my explanation doesn't work for you - have a lookhttp://en.wikipedia.org/wiki/Total_internal_reflection" [Broken]
That should have a nice explanation and plenty of pictures to explain it to you.

Last edited by a moderator: May 4, 2017
5. Apr 6, 2009

### aimslin22

Thanks, I think I get it now