Sound: the Doppler Effect

The video tutorial explains how the frequency of sound waves affects pitch, using examples like a passing train and car horn to illustrate the Doppler effect. As the source of sound moves, the frequency and pitch change, increasing as it approaches and decreasing as it moves away. This phenomenon is known as the Doppler effect, which is caused by the movement of the sound source or the listener.

What happens to the pitch of a sound when the frequency of waves changes?

• The pitch changes.

• The pitch becomes inaudible.

• The pitch remains the same.

• The pitch becomes louder.

As a train approaches you, what happens to the sound it makes?

• The sound remains constant.

• The frequency and pitch decrease.

• The frequency and pitch increase.

• The sound becomes quieter.

What is observed when a car horn passes by you?

• The pitch and frequency remain unchanged.

• The pitch and frequency increase as it moves away.

• The pitch and frequency decrease as it approaches.

• The pitch and frequency increase as it approaches and decrease as it moves away.

What is the Doppler effect?

• A change in sound direction due to wind.

• A change in sound speed due to air pressure.

• A change in frequency and pitch due to movement of the sound source.

• A change in sound volume due to distance.

Which of the following best describes the cause of the Doppler effect?

• Movement of the sound source.

• Movement of the listener.

• Change in sound medium.

• Change in air temperature.