I guess this must be simple, but it always confuses me.
When you have a prism, the light breaks to different frequencies for the different colors. Since frequency is the inverse of speed, they should have different speeds as well. But when they talk about the speed of light, it’s not specified by color is it?
Speed = wavelength x frequency. So when the frequecy goes down, the wavelength goes up. This makes sense when you think about it. If the waves get longer, fewer of them will pass a given point per second.
It all travels at the same speed in any given medium. Frequency is inverse to wavelength.
Thanks! I guess I missed a day of that class somewhere.
One caveat: In vacuum, all light travels at the same speed. In a medium, however, it does not. In most media, such as glass, lower frequencies (red) will be slower than higher ones (blue). In fact, it’s the difference in speeds which causes the colors to get separated out.
Radio waves also travel at the speed of light.
That may be an easier way to understand frequency.