The wave equation
3 marks · NormalIn a laboratory experiment, a student uses a ripple tank to measure the wavelength and speed of water waves. Describe a method the student could use to measure the frequency of the waves.
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The student can count the number of waves passing a point in a measured time period, then divide the number of waves by the time.
Common mistakes: Measuring time for one wave only
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Marking points
B1 · 1 mark · Describes counting a number of wave crests or wavefronts passing a point.
B2 · 1 mark · Measures time taken for this number to pass.
B3 · 1 mark · Calculates frequency as number of waves divided by time.
Worked solution
Count how many waves (for example, crests) pass a given point in the tank in a measured period of time (for example, 10 seconds). Divide the number of waves by the time taken to find the frequency.