Try it
Wavelength is the physical length of one full repeat. Axis rescales by decade.
Understand the result
What's going on
A wave is a pattern that repeats as it travels - a radio signal, a sound, a ripple in water. Wavelength is simply the physical length of one full repeat, measured in meters, and it depends on how fast the wave travels and how often it repeats.
The formula
λ = v / f
λ is wavelength in meters, v is wave speed in m/s, f is frequency in Hz.
Show the derivation, mnemonic, and worked example
Build it up
If a wave repeats faster (higher frequency) but travels at the same speed, each repeat has to be squeezed into a shorter stretch of space - the wavelength shrinks. If it travels faster without repeating any more often, each repeat gets to stretch out further before the next one starts - the wavelength grows. Wavelength is speed shared out among however many repeats happen per second.
Worked example
Worked example
v = speed of light = 3 × 10⁸ m/s
f = 100 MHz (FM radio) = 1 × 10⁸ Hz
λ = 3×10⁸ ÷ 1×10⁸ = 3 m
