Applications of refractive light

[Ryan B]

Homework Statement

b) White light travels from crown glass into ethanol. If the angle of incidence in crown
glass is 60.00 degrees (not sure how to insert degree sign), what is the angular spread
between the red and violet parts of the visible spectrum in the ethanol? Illustrate your
answer with a light-ray diagram.

Homework Equations

Sini = 60o
ni (for red light in crown glass) = 1.520
nr (for violet light in crown glass) = 1.376
nR (Ethanol) = 1.36

(ni)(Sini) = (nR)(SinR)

The Attempt at a Solution

For red light:

(ni)(Sini) = (nR)(SinR)
(1.52)(Sin60) = (1.36)(SinR)
SinR = (1.52)(0.866)/1.36
SinR= 0.968

I'm not sure if this is right but, if it is, I'm confused at how to get the angle on my caculator.

Can someone let me know if I'm on the right track?

Thanks!

 

[Doc Al]

Yes, that's correct.

Your calculator should have a button for inverse sine. On my calculator it's labeled sin^-1. Make sure you are in degree mode or you might end up with an answer in radians. For example: sin^-1(.5) = 30°

 

[Ryan B]

when i hit the Sin-1 button it comes up asin(... so I type in asin(0.968) and hit enter. it comes up: 1.32

why can't i get the degree? when i type in .5 (as in your example) the answer is 0.52

what gives?

 

[Ryan B]

never mind...got it