The Wave Equation

This lesson covers the wave equation and how to use it to calculate wave speed, frequency and wavelength, as required by the Edexcel GCSE Combined Science specification (1SC0). This equation applies to all types of wave — transverse and longitudinal — and is one of the most frequently examined equations in the physics papers.

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The Wave Equation

The wave equation links three quantities:

$v = f \lambda$v=fλ

Symbol	Quantity	SI Unit
v	Wave speed	metres per second (m/s)
f	Frequency	hertz (Hz)
λ	Wavelength	metres (m)

What Each Quantity Means

• Wave speed (v) — the distance travelled by the wave per second.
• Frequency (f) — the number of complete waves passing a point per second.
• Wavelength (λ) — the distance between two consecutive points in phase (e.g. crest to crest).

Exam Tip: The wave equation is on the physics equation sheet, but practising rearrangements will save you valuable time in the exam.

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Rearranging the Wave Equation