Question 21M.2.SL.TZ2.5
| Date | May 2021 | Marks available | [Maximum mark: 7] | Reference code | 21M.2.SL.TZ2.5 |
| Level | SL | Paper | 2 | Time zone | TZ2 |
| Command term | Describe, Determine, Draw, Outline | Question number | 5 | Adapted from | N/A |
A vertical tube, open at both ends, is completely immersed in a container of water. A loudspeaker above the container connected to a signal generator emits sound. As the tube is raised the loudness of the sound heard reaches a maximum because a standing wave has formed in the tube.
Describe two ways in which standing waves differ from travelling waves.
[2]
energy is not propagated by standing waves ✓
amplitude constant for travelling waves OR amplitude varies with position for standing waves OR standing waves have nodes/antinodes ✓
phase varies with position for travelling waves OR phase constant inter-node for standing waves ✓
travelling waves can have any wavelength OR standing waves have discrete wavelengths ✓
OWTTE
Outline how a standing wave forms in the tube.
[2]
«sound» wave «travels down tube and» is reflected ✓
incident and reflected wave superpose/combine/interfere ✓
OWTTE
Do not award MP1 if the reflection is quoted at the walls/container
The tube is raised until the loudness of the sound reaches a maximum for a second time.
Draw, on the following diagram, the position of the nodes in the tube when the second maximum is heard.
[1]
nodes shown at water surface AND way up tube (by eye) ✓
Accept drawing of displacement diagram for correct harmonic without nodes specifically identified.
Award [0] if waveform is shown below the water surface
Between the first and second positions of maximum loudness, the tube is raised through 0.37 m. The speed of sound in the air in the tube is 320 m s−1. Determine the frequency of the sound emitted by the loudspeaker.
[2]
✓
✓
Allow ECF from MP1
