Interference and standing waves

Answer Key - Grade 11 Science Worksheet - Building Confidence

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

1. 1.

   Two pulses overlap on a rope. At one point, with up as positive, one gives 3 cm and the other gives -1 cm. What is the combined displacement, Ari?

   2 cm
2. 2.

   Two pulses overlap on a rope. At one point, with up as positive, one gives 2.5 cm and the other gives -4 cm. What is the combined displacement, Bo?

   -1.5 cm
3. 3.

   Two pulses overlap on a rope. At one point, with up as positive, one gives -2 cm and the other gives -1.5 cm. What is the combined displacement, Esme?

   -3.5 cm
5. 4.

   In the wave diagram, what kind of interference happens, Kira?

   • Destructive
   • No interference, since they don't touch
   • Constructive
6. 5.

   In the wave diagram, what would the combined amplitude be if wave B were shifted by half a wavelength, Luz?

   Use the picture in question 4.

   • 4 cm
   • 1 cm
   • 0 cm
7. 6.

   A crest of one wave meets a trough of an equal wave. What happens there, Milo?

   • They cancel: destructive interference
   • They add together: constructive interference
   • They bounce off each other
8. 7.

   At a quiet spot in front of two speakers, the sound waves cancel. What happened to their energy, Noah?

   • It was destroyed
   • It shows up at the loud spots instead
   • It turned into light
10. 8.

    In the wave diagram, how many nodes does the string have, Ren?

    • 3
    • 4
    • 6
11. 9.

    In the wave diagram, where does the string not move at all, Tala?

    Use the picture in question 8.

    • At the antinodes
    • At the nodes
    • Nowhere, since the whole string shakes
12. 10.

    In the wave diagram, where does the string swing the most, Zee?

    Use the picture in question 8.

    • At 0.2, 0.6 and 1 m
    • At 0.4 and 0.8 m
    • At the two ends