Sound Waves
3 marks · NormalYou have a signal generator, a loudspeaker, a microphone and an oscilloscope. You want to find the frequency of a sound wave produced by the loudspeaker.
Describe how you would use the oscilloscope to find the frequency of the sound.
You observe that one complete wave on the oscilloscope trace takes 0.004 s. Calculate the frequency of the sound wave.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) Connect microphone to oscilloscope, observe the waveform. Measure time period for one complete wave on the trace using the time base. Calculate frequency using f = 1/T.
(b) 250 Hz
Common mistakes: Not mentioning measure period, or using 1/T
Show mark scheme and worked solution
Marking points
M1 (a) · 1 mark · Describes connecting microphone and observing waveform.
M1 (a) · 1 mark · Measures and explains calculation using f = 1/T, or measures period and calculates frequency.
A1 (b) · 1 mark · Correct calculation of frequency: f = 1 / 0.004 = 250 Hz.
Worked solution
a) Connect the microphone to the oscilloscope and place it near the loudspeaker. Observe the waveform on the oscilloscope. Measure the time period for one complete wave using the time base setting. Frequency is calculated by f = 1/T.
b) f = 1 / 0.004 = 250 Hz.