When you turn on a radio and hear music, at what approximate speed are the radio waves traveling?

A. the speed of light

B. 80% of the speed of light

C. 50% of the speed of light

D. less than half the speed of light

It really doesn't matter whether your radio is on or off, or what type of program content you prefer. As soon as the broadcast leaves the transmitting antenna, the radio waves travel at very close to 'c' ... the speed of light in vacuum ... even if there's nobody listening at all. (The slight, slight slow-down is due to traveling through air.)