Which of the following defines the frequency range of ultrasound?
A: below 20 Hz20\text{ Hz}20 Hz B: between 20 Hz20\text{ Hz}20 Hz and 20 000 Hz20\,000\text{ Hz}20000 Hz C: above 20 000 Hz20\,000\text{ Hz}20000 Hz D: above 20 MHz20\text{ MHz}20 MHz
A student strikes a tuning fork and uses a microphone connected to an oscilloscope to display the sound wave produced. The diagram shows the trace on the oscilloscope screen:
Calculate the frequency of this sound wave.
The student strikes a different tuning fork that produces a sound of the same loudness but a higher pitch. Describe how the amplitude and the horizontal wavelength of the trace on the oscilloscope would change, assuming the oscilloscope settings remain the same.
