Invariance of the speed of light
What Invariance of the speed of light means in Physics A-Level, as defined for AQA.
Definitions of Invariance of the speed of light
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Reference: AQA
The speed of light in a vacuum, c, is constant for all inertial observers, regardless of the motion of the light source or the observer.
Shown by the absence of any fringe shift, meaning the speed of light is the same in both arms and independent of the Earth's motion.
In vacuum the speed of light is invariant, and there is no privileged absolute rest frame.
Topics that use Invariance of the speed of light
- The Michelson-Morley experiment (A-level only) (AQA A-Level)
Related terms
- absolute motion
- Classical Galilean velocity addition
- Interference fringes
- Interferometer
- Michelson-Morley experiment
- null result
- Part-silvered mirror
- Phase difference
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