Mini-Quiz: Doppler Effect Equations for Sound

1. If a source of sound was moving toward you at 1/3 the speed of sound, what would the resulting wavelength be?

   It is impossible to find outSorry, not correct. Try another button. 2/3 the emitted wavelengthThat is correct. You have sound reasoning. 3 times the emitted wavelengthGood try, but not right. Select another answer.

2. If a horn blaring at 1000 Hz, but it is heard as 800 Hz, what is its velocity?

   0.25 the speed of sound away from youCorrect. Doppler would be proud of you. 0.5 the speed of soundOops! Wrong answer. Re-read the question and try again. 0.75 the speed of sound toward from youSorry, not correct. Try another button.

3. If you are standing next to the road, why does the pitch of the ambulance siren change as it comes toward you?

   Its angle with respect you changes as it moves toward you, thus changing the relative velocityThat is correct. You have sound reasoning. The pitch is constant until the ambulance passes byGood try, but not right. Select another answer. It is only an illusion that the pitch changes, due to changing air pressureOops! Wrong answer. Re-read the question and try again.

Pick an answer to see instant feedback. Re-read the lesson if you miss one.