Exam-style question
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Which of the following best reflects the second postulate of special relativity?.
- A.The speed of light is the same for all observers, regardless of their relative motion.
- B.The speed of light depends on the medium.
- C.The speed of light is infinite.
- D.The speed of light is zero in a vacuum.
Model answer
What a good answer should say
- The speed of light is the same for all observers, regardless of their relative motion.
Explanation
Why this works
Formula/rule: constancy of the speed of light. Substitution: none.
Working: The second postulate explicitly states that the speed of light in vacuum, c, is a universal constant and is the same for all inertial observers, independent of their relative motion. Answer: c is constant for all observers.
Units/conclusion: c = 3.00 × 10^8 m/s, same in all inertial frames.
Common mistake
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