College Physics 10th Edition by Raymond Serway,Chris Vuille

Exercise 15

The Michelson interferometer can be used to measure the index of refraction of a gas by placing an evacuated transparent tube in the light path along one arm of the device. Fringe shifts occur as the gas is slowly added to the tube. Assume 600-nm light is used, the tube is 5.00 cm long, and 160 fringe shifts occur as the pressure of the gas in the tube increases to atmospheric pressure. What is the index of refraction of the gas Hint: The fringe shifts occur because the wavelength of the light changes inside the gas-filled tube.