The GPS network consists of 24 satellites, each of which makes two orbits around the earth per day. Each satellite transmits a 50.0 W ( or even less) sinusoidal electromagnetic signal at two frequencies, one of which is 1575.42 MHz. Assume that a satellite transmits half of its power at each frequency and that the waves travel uniformly in a downward hemisphere.
(a) What average intensity does a GPS receiver on the ground, directly below the satellite, receive? ( Hint: First use Newton's laws to find the altitude of the satellite.)
(b) What are the amplitudes of the electric and magnetic fields at the GPS receiver in part ( a), and how long does it take the signal to reach the receiver?
(c) What wavelength must the receiver be tuned to?