Wavelength and frequency
3 marks · NormalA musical instrument generates a sound wave with a speed of 340 m/s and a wavelength of 0.85 m.
Calculate the frequency of the sound produced by the instrument.
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400 Hz (±2)
Also accept: 399 Hz; 401 Hz
Common mistakes: dividing the wrong way round
Show mark scheme and worked solution
Marking points
M1 · 1 mark · Uses v = f × λ or rearranges to f = v / λ. (follow-through)
M1 · 1 mark · Correct substitution: f = 340 / 0.85. (follow-through)
A1 · 1 mark · Evaluates correctly: 400 Hz (accept answers in range 398–402 Hz). (follow-through)
Worked solution
Use v = f × λ. Rearranging gives f = v / λ.