Wavelength across the spectrum

Since c = f λ and c is the same for all of them, the order by frequency is also the order by wavelength — backwards.

Figure to be added

Figure 4.13 — the electromagnetic spectrum: a wave whose wavelength shrinks from left to right, with a wavelength scale from 10⁴ m down to 10^-13 m, a frequency scale from 10⁵ Hz up to 10²¹ Hz, and pictures for each band — a radio, a television, a microwave oven, a remote control, the sun, a chest X-ray and the radiation symbol.

Radio-wave end

Lowest frequency, longest wavelength — radio waves can be longer than a building.

Gamma-ray end

Highest frequency, shortest wavelength — far smaller than an atom.

Visible light, the only part our eyes can detect, is a very narrow band near the middle.