Question

For a sound wave in air incident on a layer of water at room temperature, what is the critical angle in degrees?

Answer 1

According to the Snell's law
   
where, v_1 is the velocity of the wave in the incident medium and v_2 is the velocity of the wave in the refracted medium . Now from the definition of critical angle, we require for , . And so,
  
   
  
  
Now for sound wave incident from air medium ( for sound wave air medium is denser medium) to the interface of the air and water ( for sound, water is dilute medium ),
the velocity of sound in the air medium is
  
And the velocity of sound in the water medium is
   
And so, we have the value of the critical angle
  

answered by: anonymous