Wavelength
The distance between consecutive points in phase (e.g., between adjacent crests or troughs) in a progressive wave, measured in metres. Denoted by λ, wavelength relates to wave speed and frequency by v = fλ. Wavelength is inversely proportional to frequency for a given wave speed.
Formula
v = fλ
Real World
Wi-Fi routers operating at 2.4 GHz have a wavelength of ~12.5 cm, while 5 GHz Wi-Fi has a wavelength of ~6 cm — which is why 5 GHz signals struggle more to penetrate walls.
Exam Focus
Always convert nm to metres before substituting into v = fλ; forgetting unit conversion loses easy marks.
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