Nexrad radar uses electromagnetic radiation of frequency of 2.7 GHz to measure the speed of cloud systems. Radio waves from a transmitter are sent outward toward a cloud system, and the waves are reflected back toward the source. If the cloud system is moving, the reflected waves will be Doppler shifted. Suppose a Nexrad system observes clouds moving toward the transmitter at 21 m/s. What is the difference between the transmitted and received frequencies of the radar in this case?

Question

Quizplus · Accepted Answer

We can use the Doppler shift equation: 
Δf/f = v/c
where Δf is the difference between transmitted and received frequencies, f is the transmitted frequency (2.7 GHz), v is the velocity of the clouds (21 m/s), and c is the speed of light.

Plugging in the values, we get: 
Δf/2.7 GHz = (21 m/s) / (3 x 10^8 m/s) 
Δf = (2.7 GHz) x (21 m/s) / (3 x 10^8 m/s)
Δf = 190 Hz

Therefore, the difference between the transmitted and received frequencies of the radar in this case is 190 Hz. The answer is (A).

Nexrad Radar Uses Electromagnetic Radiation of Frequency of 2