The wave equation
4 marks · NormalA student uses a ripple tank to produce water waves. The motor is set so that the frequency of the waves is 5 Hz, and each wave has a wavelength of 0.18 m.
State the equation linking wave speed, frequency, and wavelength.
Calculate the speed of these water waves.
Give the unit for wave speed.
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) wave speed = frequency × wavelength
(b) 0.90 m/s
(c) m/s
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · States correct equation: wave speed = frequency × wavelength.
M1 (b) · 1 mark · Substitute correct values: 5 × 0.18.
A1 (b) · 1 mark · Obtains numerical answer: 0.90 m/s (accept 0.9).
B1 (c) · 1 mark · States correct unit: m/s.
Worked solution
a) The equation is: wave speed = frequency × wavelength.
b) Substitute the given values: v = 5 \times 0.18 = 0.90\ \text{m/s}.
c) The unit for wave speed is m/s.