# Question: A police radar unit transmits microwaves of frequency 3

A police radar unit transmits microwaves of frequency 3 × 1010 Hz. The speed of these waves in air is 3.0 × 108 m/s. Suppose a car is receding from the stationary police car at a speed of 140 km/h. What is the frequency difference between the transmitted signal and the signal received from the receding car?

## Answer to relevant Questions

In a common lecture demonstration of wave pulses, a piece of rubber tubing is tied at one end to a fixed post and is passed over a pulley to a weight hanging at the other end. Suppose that the distance from the fixed support ...A 200-turn coil has an area of 4 cm2 and rotates in a magnetic field of 0.5 T. (a) What frequency will generate a maximum emf of 10 V? (b) If the coil rotates at 60 Hz, what is the maximum emf?What is the reactance of a 1.0-mH inductor at (a) 60 Hz, (b) 600 Hz, and (c) 6 kHz ?(a) What is the period of oscillation of an LC circuit consisting of a 2-mH coil and a 20-μF capacitor? (b) What inductance is needed with an 80-μF capacitor to construct an LC circuit that oscillates with a frequency of ...A coil of resistance R, inductance L, and negligible capacitance has a power factor of 0.866 at a frequency of 60 Hz. What is the power factor for a frequency of 240 Hz?Post your question