- #1

leolaw

- 85

- 1

Hey guys! I need some helps on an optics problem. It is from Giancoli Chapter 23, question 41:

Question:

A beam of light enters the end of an optic fiber (attachment B). Show that we can guarantee total internal reflection at the side surface of the material (at point a), if the index of refraction is greater than about 1.42. In other words, regardless of the angle [tex]\alpha[/tex], the light beam reflects back into the material at point a.

I start by calculating the critical angle in the material (see attachment A), which is 45.233. But then I am not sure how to do the next step cause i don't seem to know what I am looking for.

Can someone just help out? Thx

Question:

A beam of light enters the end of an optic fiber (attachment B). Show that we can guarantee total internal reflection at the side surface of the material (at point a), if the index of refraction is greater than about 1.42. In other words, regardless of the angle [tex]\alpha[/tex], the light beam reflects back into the material at point a.

I start by calculating the critical angle in the material (see attachment A), which is 45.233. But then I am not sure how to do the next step cause i don't seem to know what I am looking for.

Can someone just help out? Thx