The Absorption & Emission of EM Radiation (OCR Gateway GCSE Physics: Combined Science)

Absorption of Electromagnetic Radiation

• Electrons in an atom are arranged in energy levels
  • Lower energy levels are closer to the nucleus, whilst higher energy levels are further away from the nucleus of the atom

• These electrons can absorb energy
• This happens when waves of electromagnetic radiation (such as light and heat) hit them

• When electrons absorb electromagnetic radiation, they move to a higher energy level

The electron absorbs electromagnetic radiation which causes it to move up an energy level

• Dark coloured objects are good absorbers of radiation
  • They appear dark because they do not reflect the energy that hits them

Emission of Electromagnetic Radiation

• When an electron has moved up an energy level, it will be unstable
• Eventually, it will move back down to its original energy level, which will be closer to the nucleus
• As it moves back down, It emits a wave of electromagnetic radiation

The electron emits a wave of electromagnetic radiation and moves down an energy level

• All of the colours in the visible spectrum are produced in this way
• The light waves come from electrons moving down energy levels and emitting electromagnetic radiation