BRAINCAKEInvestigating the Speed of Sound
The speed of sound in air can be measured with a signal generator, a loudspeaker, a microphone and a two-beam (dual-trace) oscilloscope.
Connect the signal generator to the loudspeaker and also to channel 1 of the oscilloscope, so channel 1 shows the signal being sent out. Connect the microphone to channel 2. Set a frequency of a few kilohertz, for example 2.0 kHz, read from the signal generator.
Place the microphone in front of the loudspeaker and move it along a metre rule until the two traces are in phase, with their peaks lined up. Record its position. Then slowly move the microphone away until the traces are in phase again: it has moved one wavelength.
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Key terms in this lesson
- wavelength
- The distance between two adjacent points on a wave that are in phase, such as one crest to the next.
- oscilloscope
- An instrument that displays how a voltage signal varies with time on a screen.
More in Waves
- Energy Transfer by Waves
- Wave Measurements
- Pulse Echo Measurements
- Transverse and Longitudinal Waves
- Earthquakes
- Phase and Phase Difference
- Superposition
- Interference
All 22 lessons in Waves · All Edexcel AS-level Physics topics