Wave speed, frequency and wavelength

Answer Key - Grade 11 Science Worksheet

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

1. 1.

   Sound travels at 343.3 m/s in air at 20 °C. What is the wavelength of a 256 Hz note, to the nearest hundredth, Bo?

   1.34 m
2. 2.

   Sound travels at 343.3 m/s in air at 20 °C. What is the wavelength of a 1000 Hz note, to the nearest hundredth, Esme?

   0.34 m
4. 3.

   Using the table, about how many times as fast is sound in water as in air, both at 20 °C, Jun?

   • About 43 times
   • About 4.3 times
   • About 1.2 times
5. 4.

   Using the table, what happens to the speed of sound in air as the air warms from 0 °C to 20 °C, Kira?

   Use the picture in question 3.

   • It stays the same
   • It falls by about 12 m/s
   • It rises by about 12 m/s
6. 5.

   Using the table, about how many times as fast as sound in 20 °C air is light, Luz?

   Use the picture in question 3.

   • About 87 million times
   • About 873,000 times
   • About 8730 times
7. 6.

   Sound moves at 343.3 m/s in air and 1481 m/s in water, both at 20 °C. What happens to a 440 Hz sound's wavelength as it enters water, Noah?

   • It grows from about 0.78 m to about 3.37 m
   • It shrinks
   • It stays the same
8. 7.

   Water-tank ripples pass from deep into shallow water, where they slow down. What stays the same, Pia?

   • The frequency
   • The speed
   • The wavelength, since the frequency changes instead
9. 8.

   A fireworks flash is seen 3 s before its bang is heard. Using 343.3 m/s for sound, about how far away is it, Ren?

   • About 343 m
   • About 114 m
   • About 1030 m
10. 9.

    Why is a fireworks flash seen before its bang is heard, Tala?

    • Light is far faster than sound
    • The flash happens first
    • Sound waits for the light to pass
11. 10.

    A tone has a period of 0.004 s. What is its frequency, Zee?

    • 250 Hz
    • 25 Hz
    • 0.004 Hz