Which characteristic of an electromagnetic radiation is affected by the medium through which it travels?
Time period
Velocity
Wavelength
Frequency
The frequency, wavelength, and time period of a wave can all change depending on the source of the wave) The velocity of an electromagnetic wave, on the other hand, is determined by the medium through which it travels. The speed of light is the velocity of a wave in a vacuum, which is considered to be 3×108m/s.the velocity of an electromagnetic wave depends upon the medium through which it is travelling. The velocity of wave in a vacuum is termed as speed of light,
Therefore, Velocity is the correct answer.