Is it true that radio waves travel faster than X-rays?

Asked by: Stephanie Ta


If the radio waves and the X-rays are travelling in a vacuum, they both travel at the same speed c [speed of light - approximately 186,000 miles/second]

All electromagnetic radiation, of which radio waves and X-rays are examples, travels at the speed c in a vacuum. The only difference between the two is that the frequency of X-rays is very much higher than radio waves.

If, on the other hand, the radio waves or X-rays are propagating through a medium other than the vacuum, their speed will generally be less than c and will depend upon the specific properties of the medium. Thus, in principle, neither can be said definitely to travel faster than the other if the medium is other than the vacuum.
Answered by: Warren Davis, Ph.D., President, Davis Associates, Inc., Newton, MA USA