Measurement of the Speed of Light in a Vacuum

Solution:

  1. Apparatus:
    • Pulsed laser source
    • Beam splitter
    • Two mirrors (one movable and one fixed)
    • Fast photodetector
    • Oscilloscope
  2. Procedure:
    • Set up the laser, beam splitter, mirrors, and photodetector in a vacuum chamber.
    • Pulse the laser and split the beam into two paths using the beam splitter.
    • Reflect the beams off the mirrors and recombine them at the photodetector.
    • Measure the time delay between the pulses using the oscilloscope.
    • Vary the distance of the movable mirror and record the corresponding time delays.
  3. Calculations:
    • Use the measured time delays and the changes in the distance of the movable mirror to calculate the speed of light cc.
  4. Error Minimization:
    • Ensure precise alignment of the optical components.
    • Use high-precision timing equipment.
    • Perform measurements in a controlled environment to minimize temperature and pressure variations.