The Doppler effect

Answer Key - Grade 11 Science Worksheet - Building Confidence

Circle the best answer, or write your answer on the line.

1. 1.

   A train horn sounds at 400 Hz; as the train approaches, it is heard at 420 Hz. By how many hertz is the pitch raised, Ari?

   20 Hz
2. 2.

   A toy buzzer on a moving cart makes 350 Hz; as it approaches, it is heard at 368 Hz. By how many hertz is the pitch raised, Bo?

   18 Hz
3. 3.

   A model train's whistle makes 500 Hz; as it approaches, it is heard at 531 Hz. By how many hertz is the pitch raised, Esme?

   31 Hz

4. Read this first

   Use this

   Wave diagram seen from above (example data):

6. 4.

   In the wave diagram, where are the ripples closest together, Jun?

   • In front of the dipper
   • Behind the dipper
   • They are evenly spaced
7. 5.

   In the wave diagram, where would a floating cork bob up and down most often, Kira?

   Use the picture in question 4.

   • Behind the dipper
   • Just as often in front as behind
   • In front of the dipper
8. 6.

   A train blows its horn as it comes toward a listener on a platform. How does the pitch sound, Milo?

   • Lower, since the train is still far away
   • The same, just louder
   • Higher than the horn's own pitch
9. 7.

   What does a listener notice as a buzzing toy car rolls past, Pia?

   • The pitch stays the same
   • The pitch drops as it passes
   • The pitch rises as it passes
10. 8.

    As a train approaches and passes, what happens to the frequency the horn itself makes, Ren?

    • It rises, then falls
    • It falls, then rises
    • It stays the same
11. 9.

    Why does the horn sound higher to the listener as the train approaches, Tala?

    • The horn is blown harder
    • Its waves reach the listener bunched together
    • Sound moves faster near a train
12. 10.

    A toy buzzer sits still on a table. Does a listener hear a Doppler shift, Zee?

    • Yes, a higher pitch
    • Yes, a lower pitch
    • No, since nothing is moving