© Oxford University Press 2011 IP1.24.5 The wave equation The wave equation

© Oxford University Press 2011

IP1.24.5 The wave equation

The wave equation



The wave equation

The speed of a wave depends on its frequency and its wavelength. They are related.

If the wave speed is called v, the frequency f and the wavelength , then:

Wave speed

metres/second (m/s)

=

=

frequency

hertz (Hz)

wavelength

metres (m)

v = f



Dylan is standing on the end of a pier. He measures the water waves going past him. The wavelength of each wave is 1.3 m. He counts 2 waves every second. Find the wave speed.

Wave speed = frequency wavelength

v = 2 Hz 1.3 m

v = 2 1.3 m/s

v = 2.6 m/s



Find the speed of a wave whose wavelength is 40 m and frequency is 100 Hz.

Wave speed = frequency wavelength

v = 100 Hz 40 m

v = 100 40 m/s

v = 4000 m/s



A flute produces a note with a wavelength of 75 cm. The speed of sound is 330 m/s. Find the frequency of the note.

frequency =

frequency =

frequency = 440 Hz

wave speed

wavelength

330 m/s

0.75 m



What is the frequency when the wave speed is 450 m/s and the wavelength is 4.6 m?

frequency =

frequency =

frequency = 97.8 Hz

wave speed

wavelength

450 m/s

4.6 m



A radio station transmits waves with a frequency of 120 MHz. The radio waves travel at 3 108 m/s. Find the wavelength of the radio waves.

wavelength =

wavelength =

wavelength = 2.5 m

wave speed

frequency

3 108 m/s

1.2 108 Hz



A speaker produces sound at a frequency of 6.6 kHz. The speed of sound is 330 m/s. Calculate the wavelength.

wavelength =

=

= 0.05 m

= 5 cm

wave speed

frequency

330 m/s

6600 Hz

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© Oxford University Press 2011 IP1.24.5 The wave equation The wave equation