Physics (AS & A Level) · May / June 2020 · Paper 12 · Question 23

A microphone connected to the Y-plates of a cathode-ray oscilloscope (CRO) is placed in front of a loudspeaker. The trace on the screen of the CRO is shown. The time-base setting is 0.5 ms cm⁻¹ and the Y-plate sensitivity is 0.2 mV cm⁻¹. What is the frequency of the sound from the loudspeaker and what is the amplitude of the trace on the CRO?

1. Afrequency 330 Hz, amplitude 0.6 mV
2. Bfrequency 330 Hz, amplitude 1.2 mV
3. Cfrequency 670 Hz, amplitude 0.6 mV
4. Dfrequency 670 Hz, amplitude 1.2 mV

As printed in the paper