Physics
Light
Speed of Light Measurement
XI
⚡ Quick Summary
Methods for measuring the speed of light including Roemer, Fizeau, Foucault, and Michelson methods.
No specific formulas are listed in the text, but the underlying principle for Fizeau and Michelson methods involves: Speed of Light = Distance / Time. The time is determined by the angular speed of the rotating component and the geometry of the setup.
- Roemer Method: One of the earliest methods to estimate the speed of light based on observations of the eclipses of Jupiter's moons.
- Fizeau Method: Uses a rotating toothed wheel to interrupt a beam of light, which is then reflected back from a distant mirror. By adjusting the speed of the wheel, the light can be blocked on its return, allowing the calculation of the speed of light.
- Foucault Method: Employs a rotating mirror to deflect a beam of light, which is then reflected back from a fixed mirror. The angular displacement of the returning beam is used to determine the speed of light. This method can also be adapted to measure the speed of light in different media, such as water.
- Michelson Method: Refines the Foucault method using a system of rotating mirrors and a long path length to precisely measure the speed of light.