Minimum index of refraction for total internal reflection in a prism

[aimslin22]

Homework Statement

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?

Homework Equations

Snell's law

nsinx=nsinx

The Attempt at a Solution

I think know how to do it, I just need to know what "total internal reflection" means. Please help

 

[DrMon]

Total internal reflection is what occurs when the light hits a medium boundary at such a wide angle the the light completely 'bounces' off the boundary, without crossing it.
For example, if the light hits a boundary 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 boundary at is the angle is bounces back at.

 

[aimslin22]

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

 

[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"
That should have a nice explanation and plenty of pictures to explain it to you.

 

[aimslin22]

Thanks, I think I get it now