The laws of refraction and reflection are the same for sound as for light. the speed of sound in air is 340 m/s and in water it is 1510 m/s. if a sound wave approaches a plane water surface at an angle of incidence of 12.0 °, what is the angle of refraction?

Amichelson interferometer operating at a 600 nm wavelength has a 3.02-cm-long glass cell in one arm. to begin, the air is pumped out of the cell and mirror m2 is adjusted to produce a bright spot at the center of the interference pattern. then a valve is opened and air is slowly admitted into the cell. the index of refraction of air at 1.00 atm pressure is 1.00028.how many bright-dark-bright fringe shifts are observed as the cell fills with air?