An ordinary light bulb gives off visible white light. If you were moving toward it at nearly the speed of light, it would appear to be emitting X rays, while if you moving away from it at the same high speed, it would appear to be emitting radio waves. This is an example of what wave phenomenon
Doppler shift is also known as Doppler effect. It is simply the change in frequency of light, caused by the relative motion of the source and the observer.
