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Energy levels and the emission of radiation

The spectrum of a gas depends on the separation of the energy levels within the atoms of the gas. In an unexcited gas the electron will be in the ground state but it can be excited to an upper level by an input of energy.
This energy can be electrical, radiation, thermal or by collision with a fast moving particle.

When an electron falls from one level to another energy is emitted in the form of a quantum of radiation.

The energy of this quantum and therefore its frequency and wavelength is determined by the difference in energy between the two levels.

The greater the energy difference the greater the frequency.
© Keith Gibbs 2009