# Snell's Law and critical angle

## Homework Statement

The critical angle of a certain plastic in air is 37.3 degrees. Wats the critical angle of the same plastic if its immersed in water?

## Homework Equations

n1sin( theta)= n2sin(theta)

## The Attempt at a Solution

Nair= 1.00
1.00sin37.3/1.33 = sin(theta)
sin(theta)= .455
inverse sin (theta) = 27.1 degrees

Is that right?

No. I think it should be:
<< complete solution deleted by berkeman >>

Last edited by a moderator:
berkeman
Mentor
No. I think it should be:
<< complete solution deleted by berkeman >>

Please do not post complete solutions to homework/coursework questions. Instead, provide hints and tutorial advice. The original poster (OP) must do the buld of the work. The Rules link at the top of the page explains how we treat homework here on the PF.

rl.bhat
Homework Helper

## Homework Statement

The critical angle of a certain plastic in air is 37.3 degrees. Wats the critical angle of the same plastic if its immersed in water?

## Homework Equations

n1sin( theta)= n2sin(theta)

## The Attempt at a Solution

Nair= 1.00
1.00sin37.3/1.33 = sin(theta)
sin(theta)= .455
inverse sin (theta) = 27.1 degrees

Is that right?
No.
What is the relation between the refractive index and the critical angle?
Find the refractive index of the plastic.