Question

Police radar guns measure the speed of moving vehicles by transmitting electromagnetic waves at a vehicle and detecting a Doppler shift in the reflected wave. Suppose a police radar transmits at a frequency of 26.8 GHz and receives a wave reflected from a car moving toward the radar at 66.0 mph. Find the frequency shift

Answer 1

Answer:

Frequency shift, f = 5270.66

Explanation:

It is given that,

Velocity of the car, v = 66 mph = 29.50 m/s

Frequency transmitted by a police radar, $F_s=26.8\ GHz=26.8\times 10^9\ Hz$

Frequency shift is given by :

$f=\dfrac{2vF_s}{c}$

$f=\dfrac{2\times 29.50\ m/s\times 26.8\times 10^9\ Hz}{3\times 10^8\ m/s}$

f = 5270.66 Hz

So, the frequency shift is 5270.66 hertz. Hence, this is the required solution.