A radar gun can determine the speed of a moving automobile by measuring the difference in frequency between emitted and reflected radar waves. What process is used in determining the speed of the car?

Question 7 options:

resonance

refraction

diffraction

doppler effect

The Doppler effect is responsible for calculating the speed of a moving car on the roads.

A radar gun can determine the speed of a moving automobile by measuring the difference in frequency between emitted and reflected radar waves.

When the objects move, the wavelength and frequencies also change as they move towards or away from the observer.

Doppler effect estimates the change in frequency or wavelength of the source which is in motion. This way we can calculate the speed of the object.

Therefore, the Doppler effect is responsible for calculating the speed of a moving car on the roads.

For more details, refer to the link:

link

Doppler effect.

Explanation:

The velocity of the moving car affects the wavelengths of the reflecting  radio waves according to the principle of Doppler effect. Therefore, for a car moving away from the radar gun, the wavelength of the radio waves is increased, and for a car moving towards the gun, the wavelength is decreased. The degree of increase or decreases depends on the speed of the car, so if you know how much a wavelength has changed, you know the velocity of the car.

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