# Thread: The Light Trouble that's Hard

1. Hi guys, i was wondering why total internal reflection occurs. I understand all the formula's and so on but how does it occur???? :P
Thanks

2.

3. It occurs because the light enters a substance and refracts but cannot escape the substance because the angle of incidence is no longer greater than the critical angle.

4. Originally Posted by Keith
It occurs because the light enters a substance and refracts but cannot escape the substance because the angle of incidence is no longer greater than the critical angle.
For total internal refraction angle of incidence should be greater than critical angle not less. The light rays should also pass from denser to rarer medium.
We know that when rays travel from denser mediun to rarer medium they bend away from the normal and so for an angle of inciidence the angle of refraction would be 90 degree this angle is critical angle and when the angle of incidence is more than the critical angle the rays would come back in the same medium. this phenomenon is called total internal reflection.

5. Ehh, its been too long since I've taken physics.

6. Check out evanescent waves.

http://en.wikipedia.org/wiki/Evanescent_wave

7. I don't understand why it has to be a near-field wave? Doesn't light react the same regardless of the distance?

I took a non-calculus based physics course in tenth grade. We really didn't learn anything I realize now. Next year I'll be taking the AP Physics course which is a College Board thing as I'm sure a few of you know. So I'll be asking tons of questions during that I'm sure judging on how much I remember.

 Bookmarks
##### Bookmarks
 Posting Permissions
 You may not post new threads You may not post replies You may not post attachments You may not edit your posts   BB code is On Smilies are On [IMG] code is On [VIDEO] code is On HTML code is Off Trackbacks are Off Pingbacks are Off Refbacks are On Terms of Use Agreement