An interferometer can be used to measure the index of refraction of a gas. Two i
ID: 2188600 • Letter: A
Question
An interferometer can be used to measure the index of refraction of a gas. Two identical, transparent rectangular containers 20.0 cm long (internally) are placed in the arms of an interferometer. Both initially are filled with air. As the air in the first container is slowly replaced with a gas of unknown mixture, 50 bright fringes are observed to move across the viewing scope. The air is then slowly pumped out of thesecond container (i.e. to create a vacuum); during this process 172 fringes are observed to pass through the viewing scope. If the interferometer uses light of wavelength 530 nm (in a vacuum) find the index of refraction of the unknown gas and the index of refraction of air.
Explanation / Answer
index of refraction is 0.01 index of refraction of air is 0.112