Describing waves
4 marks · NormalA loudspeaker produces a sound wave with a frequency of 450 Hz. Each wave has a time period of 0.0022 seconds.
State the equation relating frequency and time period for a wave.
Using the equation, calculate the frequency expected if the time period is 0.0022 s.
Suggest why the calculated frequency and measured frequency might not match exactly.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) f = 1/T
(b) f = 1/0.0022 = 454.5 Hz
(c) Any correct suggestion, e.g. measurement errors or rounding in the values used.
Must show: correct equation, correct calculation steps, any valid reason for mismatch
Common mistakes: Using T = f × t instead of T = 1/f
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · States correct equation: f = 1/T.
M1 (b) · 1 mark · Substitutes: 1 / 0.0022 or equivalent, or correct working seen.
A1 (b) · 1 mark · Evaluates answer correctly: 454.5 Hz (accept any value in range 454–455 Hz). (follow-through)
B1 (c) · 1 mark · Gives a correct reason for a difference (e.g. measurement error, rounding, instrument precision).
Worked solution
a) The equation is f = 1/T.
b) f = 1 / (0.0022 s) = 454.5 Hz.
c) The calculated and measured values might not match due to errors in measuring time period, rounding, or the limits of the measurement equipment.