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.
Which travels faster in a vacuum a radio wave or a light wave?
Why does it take so long for the radio waves to travel through space? Actually, radio waves travel very quickly through space. Radio waves are a kind of electromagnetic radiation, and thus they move at the speed of light. The speed of light is a little less than 300,000 km per second.
Do all radio waves travel same speed?
All electromagnetic waves travel at the same speed through empty space. That speed, called the speed of light, is about 300 million meters per second (3.0 x 108 m/s). Nothing else in the universe is known to travel this fast.
Do gamma rays travel faster than radio waves?
In a vacuum all light travels the same speed no matter what the wavelength or frequency. Gamma radiation has a smaller wavelength and larger frequency, radio waves a smaller frequency and larger wavelength.