All EM radiation travels at c = 3.0 × 10⁸ m s⁻¹ in air. Click on any region of the spectrum below to explore its properties.
Speed of Light Equation
Energy of a Photon
Drag the slider to explore the full EM spectrum. Watch how frequency and wavelength are inversely related.
Energy levels in atoms and molecules are quantised — electrons can only occupy specific discrete energy levels. A photon is only absorbed if its energy exactly matches the energy difference between two levels: ΔE = hν = hc/λ.
ABOUT THIS SIMULATION
Select a radiation type to see how electrons in a hydrogen-like atom respond to different types of electromagnetic radiation. Each type causes a different kind of transition.
h = 6.63 × 10⁻³⁴ J s
c = 3.0 × 10⁸ m s⁻¹
The Lyman, Balmer and higher series result from transitions back to n=1, n=2 etc. The arrows show which radiation causes which transition.