EM Spectrum Trainer

c = fλ with c = 3.00 × 10⁸ m s⁻¹, so each wavelength boundary gives the matching frequency.
Going gamma → radio, wavelength increases, and frequency and photon energy (E = hf) decrease.
Visible light runs from violet (~400 nm) to red (~700 nm): ROYGBIV, red has the longest wavelength.
Boundaries are approximate and sources differ slightly. Gamma and X-rays overlap: they are told apart by their source (nuclear vs electron transitions), not by wavelength. This trainer uses the standard textbook values in the table.