8/19/2019 Doppler Effect Worksheet

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Name:_______________________________ Period: ______ Date: _____/_____/_____

Doppler Effect WS (614)

Have you ever noticed that the sound of a fire truck’s siren changes as it passes you? This isbecause the sound waves in front of the truck are compressed as it comes towards you andstretched out behind the truck as it moves away from you. Remember, a shorter wavelengthresults in a higher frequency (and higher pitch), and a longer wavelength results in a lowerfrequency (and lower pitch). This apparent change in frequency is called the Doppler effect.

1. When an automobile moves towards a listener, the sound of its horn seems relatively

a. Low pitched b. High Pitched c. Normal

2. When the automobile moves away from the listener, its horn seemsa. Low pitched b. High Pitched c. Normal

3. The changed pitch of the Doppler effect is due to changes ina. Wave speed b. wave frequency

4. Circle the letter of each statement about the Doppler Effect that is true.a. It occurs when a wave source moves towards an observerb. It occurs when an observer moves towards a wave source

c. It occurs when a wave source moves away an observerd. It occurs when an observer moves away a wave source

5. True / False: A moving wave source does not affect the frequency of the waveencountered by the observer.

6. True / False: A higher frequency results when a wave source moves towards anobserver.

8/19/2019 Doppler Effect Worksheet

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7. Two fire trucks with sirens on speed towards and speed away from an observer asshown below.

truck speeding towards truck speeding away

a. Which truck produces a higher than normal siren frequency?

b. Which truck produces a lower than normal siren frequency?