I have a question about the speed of EM radiation. As far as i understand, all Frequencies of EM radiation travels at the same speed. ie, will reach point A to point B in the same amount of time.... But wouldnt that mean that as you go from one end of the spectrum to the other, the waves are travelling at different speeds due to the fact that the wave length and amplitude are changing? Kind of like a straight line, 10 mile care race between two cars in which they have to zig zag the entire race. One car has to zig zag 50 times and the other car has to zig zag 100 times. (50hz and 100hz) Each cars zig zag pattern travels the same distance to the left and right of the line. (equal amplitude) now if both cars complete the 10 miles in exactly the same amount of time then technically one car actually travelled faster because he drove a longer distance. Due to zig zagging 50 more times than the other. Would this not be true for different frequencies of the EM spectrum? or is our "up and down" "back and forth" wave concept really just for our own mental picturing? Thanks anyone.