Electromagnetic Spectrum

Absorption and Reflection

A substance can do the following to a wave when hit: absorb, transmit, refract or reflect. Substances will do different things according to the wavelength.

For example, a block of wood

  • will reflect light from the visible light spectrum.
  • will absorb infrared, increasing its temperature
  • let radio waves travel straight through and be transmitted out the other side.


Different parts of the EM spectrum have different dangers associated with them:

  • Radio waves - None
  • Microwaves - Internal heating of body cells
  • Infrared - Skin burns
  • Visible light - None - though if very intense can cause blindness
  • Ultraviolet - Damage to surface cells and eyes leading to cancer and__ eye conditions__
  • X-rays - Mutation or damage to cells in the body
  • Gamma rays - Mutation or damage to cells in the body


Different parts of the EM spectrum have different uses:

  • Radio waves - Broadcasting, communications and satellite transmissions
  • Microwaves - Cooking, communications and satellite transmissions
  • Infrared - Cooking, thermal imaging, short range communications, optical fibres, television remote controls and security systems.
  • Visible light - Vision, photography and illumination
  • Ultraviolet - Security marking, fluorescent lamps, detecting forged bank notes and disinfecting water
  • X-rays - Observing internal structure of objects, airport security scanners and medical x-rays
  • Gamma rays - Sterilising food and medical equipment and the detection of cancer and its treatment


Atoms and nuclei have the ability to absorb and __transmit __a part of the EM spectrum.

Changes within atoms and the nuclei of atoms can result in EM waves being produced or absorbed over a wide range of frequencies.Electromagnetic Spectrum, figure 1Gamma rays are produced in the __nucleus __only.

Where in the atom are gamma rays produced?
Can infrared be used for cooking and detecting forged bank notes?
What four things can a substance do with the EM spectrum that is incident upon it?
Your answer should include: Absorb / transmit / reflect / refract