Question

why speed of light is constant ?

Answer 1

heye my dear sweet friend here is your answer

3×10^8

is your answer

hope it's help

Answer 2

Einstein's theory of special relativity sets of the speed of light, 186,000 miles per second (300 million meters per second). The speed of light is constant, or so textbooks say. But some scientists are exploring the possibility that this cosmic speed limit changes, a consequence of the nature of the vacuum of space.