Measuring the Speed of Light (Foucault Method)
In this experiment, a beam of light from a laser was reflected off of a rotating mirror to a fixed mirror, and then reflected back to the rotating mirror. The returning light was focused to a point image in a microscope. Due to the continued rotation of the mirror while the light was in transit from the rotating mirror, to the fixed mirror, and back, the beam was reflected into the microscope at an altered angle, resulting in a displacement of the point image. Measurement of this displacement, along with distance parameters from our setup, known as the Foucault Method, allows for the speed of the light to be calculated. The mean speed of light calculated from this experiment was (2.9972 ± 0.0139) x 108 m/s.
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