Guided science

Light, waves and atoms

A wave is a propagating disturbance that can transfer energy and information without requiring a net transport of matter over the same distance.

Begin here

A wave is a propagating disturbance that can transfer energy and information without requiring a net transport of matter over the same distance.

Connect the ideas

A wave is a propagating disturbance that can transfer energy and information without requiring a net transport of matter over the same distance.

Spectroscopy studies how matter emits, absorbs or scatters electromagnetic radiation as a function of wavelength, frequency or energy.

Electron configuration describes how electrons occupy available atomic states. This arrangement is central to periodic trends and helps explain why elements in the same group often react in related ways.

Concrete checkpoint

Light behaves as an electromagnetic wave and exchanges energy in quanta. Atomic spectra reveal discrete energy differences and are among our clearest windows into atomic structure.

Continue deeper

Waves · Spectroscopy · Electron Configuration

Reference spine

01Frequency and wavelength are linked

02Photon energy follows frequency

03Atoms select discrete energies

Frequency and wavelength are linked

In vacuum, c = λν. A shorter wavelength therefore means a higher frequency; neither quantity is an independent label once propagation speed is fixed.

Photon energy follows frequency

Planck’s relation E = hν says higher-frequency photons carry more energy individually. Intensity, however, also depends on how many photons arrive and is not identical to photon energy.

Atoms select discrete energies

Bound electrons have quantized energies. Only photons matching allowed energy differences are absorbed or emitted strongly, creating line spectra that can identify elements and probe physical conditions.

Worked example

Which photon has more energy, 400 nm or 700 nm light?

The 400 nm photon, because photon energy is inversely proportional to wavelength in vacuum.

Common traps to avoid

A spectrum line is not a miniature coloured electron orbit.
Shorter wavelength means higher photon energy, not automatically higher total beam power.