# Grade 11 physics

1. Jan 16, 2010

### Shaley

light travels from ethanol intro crown glass. what's the brewster angle in this situation? illustrate your answer with a light ray diagram. what's the signifcance of this angle of incidence?

n1=1.36for ethanol
nR=1.52 for crown glass

tanangleB=nR/ni
=1.52/1.36
=1.12 (48.2 degrees)

the only thing that I have in the diagram is the face that both the incident and reflected rays are 48.2 degrees in the ethanol..not even sure if that is right.

not sure how to draw it or what the signicance is....please explain.

2. Jan 16, 2010

### Matterwave

The Brewster's angle is the incident angle at which only S-polarized light is reflected. Therefore, the reflected beam is S-polarized, while the refracted beam has both S and P polarizations.

The point is that the Brewster's angle only gives you the angle of incidence, and not the angle of reflection or angle of refraction. To get those two angles, you need to apply the known reflection and refraction rules.

Reflection is easy. Refraction requires Snell's law.