The Wave Equation

Exam code: 5054

Written by: Ashika|Reviewed by: Caroline Carroll|Updated 2 July 2026

The Wave Equation

$v = f \times λ$

Where:
- v = wave speed in metres per second (m/s)
- f = frequency in hertz (Hz)
- λ = wavelength in metres (m)

The wave speed equation may need to be rearranged, which can be done using this formula triangle:

Worked example

A wave in a pond has a speed of 0.15 m/s and a time period of 2 seconds. Calculate:

a) The frequency of the wave

b) The wavelength of the wave

Answer:

(a)

Step 1: List the known quantities

Step 2: Write out the equation relating time period and frequency

$f = \frac{1}{T}$

Step 3: Rearrange for frequency, f, and calculate the answer

$f = \frac{1}{2}$

Frequency, f = 0.5 Hz

(b)

Step 1: List the known quantities

Step 2: Write out the wave speed equation

$v = f \times λ$

Step 3: Rearrange the equation to calculate the wavelength

$λ = \frac{v}{f}$

Step 4: Use the frequency you calculated in part (a) and put the values into the equation

$λ = \frac{0.15}{0.5}$

Wavelength, λ = 0.30 m

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