Edexcel IGCSE Physics 3.27P Sound frequency practical

Practise using oscilloscope traces to measure sound-wave period, convert time-base squares into seconds, and find frequency with f = 1/T.

Exam points

measure one full cycle on an oscilloscope trace and convert squares using the time base
use f = 1/T to determine frequency, then compare it with the human hearing range
describe a setup with a microphone, steady trace and at least one complete cycle visible

[Maximum number: 3]

Magnetic Resonance Imaging (MRI) machines can take scans of the inside of a patient.

During the scan, music can be played through a loudspeaker to the patient.

The oscilloscope trace in the diagram represents a sound played to the patient.

Figure for Question 3.27P Sound frequency practical question 1 — Edexcel IGCSE Physics

Determine the period of the sound wave.

period = ............ s

Marking points:
- period given as 4 squares
- correct use of x scale
- subsequent correct evaluation of period

Example:
$\text{period}=4\ \text{squares}$ $\text{period}=4\times\frac{0.50}{1000}$ $\text{period}=2.0\times10^{-3}\ \mathrm{s}$

Accept:
- ECF candidate's reading of period in squares
- $2.0\ \mathrm{ms}$

Marking guidance:
- Deduct 1 mark for a power-of-ten error.

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3.27P Sound frequency practical question 1