The Wave Equation Flashcards

All 6 cards in this deck

State the wave equation linking wave speed, frequency and wavelength, with units.

wave speed (m/s) $=$ frequency (Hz) $\times$ wavelength (m), i.e. $v = f\lambda$

How do you calculate the frequency of a wave from its speed and wavelength?

e.g. speed $= 300$ m/s, wavelength $= 2$ m

1. Rearrange $v = f\lambda$: $f = v \div \lambda$
2. Substitute: $300 \div 2$
3. $f = 150$ Hz

What is $v = f\lambda$ rearranged to make wavelength the subject?

$\lambda = v \div f$

What is 1 GHz in hertz?

$1 \times 10^{9}$ Hz (1 MHz $= 1\times10^{6}$ Hz, 1 kHz $= 1000$ Hz).

True or false? If the frequency of a wave doubles while its speed stays the same, the wavelength doubles.

False. The wavelength halves, because $v = f\lambda$ and $v$ is constant.

Which units must be used in $v = f\lambda$ to give a speed in m/s?

Frequency in hertz (Hz) and wavelength in metres (m).