Answer to Question #106374 in Electricity and Magnetism for Will

Question

Find the critical angle for light traveling from a ruby (n=1.776) into air

Answer 1

Critical angle from ruby in air

$$sin(\alpha)=\frac{1}{n}$$ $$\alpha=arcsin(\frac{1}{n})=arcsin(\frac{1}{1.776})=34^o$$