Find the speed of light in medium 'a' if speed of light in medium 'b' is `c//3`, where c =speed of light in vacuum and light refracts from medium 'a' to medium 'b' making `45^(@)` and `60^(@)`, respectively, with the normal.

Explanation

From Snell's Law
`mu_(a) sin theta_(a)=mu_(b) sin theta_(b)`
`rArr c/v_(a) sin theta_(a)=c/v_(b) sin theta_(b)`
`c/v_(a) sin 45^(@)=c/(c//3) sin 60^(@)`
`rArr v_(a)=(sqrt(2) c)/(3sqrt(3))`