CP6 Determine the Speed of Sound in Air Flashcards
Reduce uncertainty?
Use of an oscilloscope to find the frequency
Calibrating oscilloscope
Maximise the distance between microphone as the time interval is very small
How?
Set up a system with a signal generator, oscilloscope, speaker and microphone with a ruler to measure the distance between them.
Vary the distance between them until a peak and trough line up to find one wavelength.
Move the mic to find 2nd and 3rd wavelengths and divide by 2 or 3
find wavelength and find the period using the oscilloscope
v= fλ
What should be displayed on the oscilloscope?
Signal sent by speaker and the signal received by the mic
What happens at 1 wavelength?
The peak of one graph meets the trough of the other.
How to find frequency?
1/ period of the oscilloscope screen
Comment on the sources of uncertainty.
The oscilloscope traces are quite thick
Resolution of the screen
Why does the moving from the peak touching a trough to another peak touching a trough show 1 wavelength?
As the x-axis shows a period, we can tell that sound takes an extra period to travel that distance
Why is 4khz a good frequency?
It’s able to be displaced with a good resolution using a ruler
