The velocity of sound in air is about 330m/s, and in water is about 1700m/s. Calculate the critical angle for sound leaving air and entering water.

1 answer

sinTheta*1=sin90*(330/1700)
theta= arcsin( )=11.19 degrees

That speed is a bit high for water. https://hypertextbook.com/facts/2000/NickyDu.shtml