PASCO WA-9316A Complete Microwave Optics System - Manual (Page 26)

Experiment Guide Experiment 9: Michelson Interferometer
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• Minima traversed = _________________________.
• x
2
= _________________________.
•  = _________________________.
Question
1. You have used the interferometer to measure the wavelength of the microwave radiation. If you already knew the wave-
length, you could use the interferometer to measure the distance over which the Reflector moved. Why would an optical
interferometer (an interferometer using visible light rather than microwaves) provide better resolution when measuring
distance than a microwave interferometer?


An Idea for Further Investigation
Place a cardboard box between the Partial Reflector and Reflector A. Move one of the reflectors until the meter deflection is a
maximum. Slowly fill the box with styrene pellets while observing the meter deflections. On the basis of these observations,
adjust the position of Reflector A to restore the original maximum. Measure the distance over which you adjusted the reflector.
Also measure the distance traversed by the beam through the pellets. From this data, can you determine the styrene pellets’
index of refraction at microwave frequencies? The wavelength of electromagnetic radiation in a material is given by the rela-
tionship
 = 
0
/n; where  is the wavelength, 
0
is the wavelength in a vacuum, and n is the index of refraction of the material.
Try boxes of various widths. You might also try filling them with a different material.