Microwaves are electromagnetic waves used in broadcasting and telecommunications. When do these waves increase in frequency?
a. when the source moves away from you
b. when the source moves toward you
c. when you move away from the source
d. when you move away from the source and the source moves away from you

Question

Microwaves are electromagnetic waves used in broadcasting and telecommunications. When do these waves increase in frequency?
a. when the source moves away from you 
b. when the source moves toward you 
c. when you move away from the source
d. when you move away from the source and the source moves away from you

kropot72 · Answer

The Doppler effect is the increase in frequency when the source and the observer are moving closer together and the decrease in frequency when the source and the observer are moving further apart.

anonymous · Answer

EM waves travel at the speed of light, so the source would have to be travelling close to the speed of light for there to be any noticeable change in frequency

kropot72 · Answer

Speed detection by microwave radar makes use of the Doppler effect. You can find more details here: http://hyperphysics.phy-astr.gsu.edu/hbase/sound/radar.html