Question

Which of the following was one of the two basic postulates of special relativity formulated by Albert Einstein?

• A. Accelerating reference frames are equivalent to non-accelerating reference frames.
• B. The speed of light does not change in all inertial reference frames.
• C. Speed of photons is more than the speed of light waves.
• D. Mass is converted completely into energy when moving at the speed of light.
• E. Physical laws are relative.

Answer 1

Answer: (B)

The speed of light does not change in all inertial reference frames.

The most basic postulate of Einstein's special theory of relativity is that the light travels with the constant speed equal to $c$ in all inertial reference frames.