A room contains air in which the speed of sound is`340m//s.k`.The walls of the room are made of concerte in whichthe speed of sound is`1700m//s`(a)Find the critical angle for total internal relfection of sound at the concrete-air boundary.(b)in which medium must the sound be travelling to undergo toal internal refelection?

Answer

(a)`sin^(-1)((1)/(5))`;(b) air

Explanation

(a)`mu_(2)=(sin i)/(sin r)=(V_(air))/(V_(concrete))`
`(sin C)/(sin90^(@))=(340)/(1700)`
`C=sin^(-1)((1)/(5))`,(b) air