Which of the following quantities is always the same to all observers?

Name: Which of the following quantities is always the same to all observers?
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Question

Quizplus · Accepted Answer

The speed of light is always the same to all observers, regardless of their motion or relative position. This is a fundamental principle of special relativity. Time intervals, the speed of an object, and the speed of sound all depend on the observer's frame of reference and can change depending on their relative motion.

Which of the Following Quantities Is Always the Same to All