Question

How can a Michelson interferometer be used to measure the index of refraction of a gas, including air?

a. By introducing a gas sample into one of the interferometer arms and measuring the resulting interference pattern shift.
b. By adjusting the angle of the beam splitter to account for gas dispersion.
c. By changing the wavelength of the light source and observing the resulting changes in interference fringes.
d. By increasing the air pressure in one of the interferometer arms to vary the refractive index.

Answer 1

A Michelson interferometer measures the index of refraction of a gas by counting the shift in interference fringes caused by introducing the gas into one of the interferometer's arms, using the known wavelength of light.

Step-by-step explanation:

The Michelson interferometer can be used to measure the index of refraction of a gas by introducing a gas sample into one of the interferometer arms and measuring the resulting interference pattern shift. This is accomplished by placing a chamber into the path of one of the beams inside the interferometer.

As the gas enters the chamber and the refractive index changes, the optical path length changes, causing a shift in interference fringes that can be observed. By counting the number of fringes that move past a reference point while the gas is introduced, and knowing the wavelength of the light used, the index of refraction of the gas can be calculated using the formula resulting from the interference condition of the Michelson interferometer.