Exam-style question
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What is the value of the speed of light in vacuum, and does it depend on the motion of the source or observer?.
Model answer
What a good answer should say
- The speed of light in vacuum is 3.00×10^8 m s^−1, and it is the same for all observers regardless of the motion of the source or observer.
Explanation
Why this works
Rule: The constancy of the speed of light in vacuum is a postulate of special relativity. Substitution: none.
Working: none. Answer: 3.00×10^8 m s^−1.
Units: m s^−1. Conclusion: The speed of light is invariant and does not depend on relative motion.
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