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Lesson: Interferometry

Worksheet: Interferometry • 6 Questions


In a Michelson interferometer, light of wavelength 632.8 nm from a He-Ne laser is used. When one of the mirrors is moved by a distance , 8 fringes move past the field of view. What is the value of the distance ?

  • A
  • B
  • C
  • D
  • E


An experimenter detects 251 fringes when the movable mirror in a Michelson interferometer is displaced. The light source used is a sodium lamp, wavelength 589 nm. By what distance did the movable mirror move?


What is the distance moved by the traveling mirror of a Michelson interferometer that corresponds to fringes passing by a point of the observation screen? Assume that the interferometer is illuminated with a 606 nm spectral line of krypton-86.

  • A m
  • B m
  • C m
  • D m
  • E m


In a thermally stabilized lab, a Michelson interferometer is used to monitor the temperature to ensure it stays constant. The movable mirror is mounted on the end of a 1.00-m-long aluminum rod, held fixed at the other end. The light source is a He Ne laser, . The resolution of this apparatus corresponds to the temperature difference when a change of just one fringe is observed. Find the temperature difference. Use a value of for the thermal expansion coefficient of aluminum.


A 5.08-cm-long rectangular glass chamber is inserted into one arm of a Michelson interferometer using a 633-nm light source. This chamber is initially filled with air at standard atmospheric pressure but the air is gradually pumped out using a vacuum pump until a near perfect vacuum is achieved. How many fringes are observed moving by during the transition?