Index of Refraction

The speed of a sound wave is 344 m/sec in air and 1320 m/sec in water.

a) Which medium has the higher “index of refraction” for sound?

B) What is the critical angle for a sound wave incident on the surface between air and water?
c) for total internal reflection to occur must the sound wave be traviling in the air oor in the water ?

d) use ypur result to explain why its possible to hear people on the opposite shore of river or small lake to clear ?