A room contains air in which the speed of sound is 343 m/s. The walls of the room are made of concrete, in which the speed of sound is 1 850 m/s.
(a) Find the critical angle for total internal reflection of sound at the concrete–air boundary.
(b) In which medium must the sound be traveling in order to undergo total internal reflection?
(c) “A bare concrete wall is a highly efficient mirror for sound.” Give evidence for or against this statement.