Yr 10 Physics


Introduction to Radiation

A radioactive nucleus is unstable and will emit radiation. There are 3 main types.


  • Strongly ionising
  • Only travels a few centimetres in air
  • Stopped by a thin sheet of paper


  • Ionising Radiation
  • Penetrates card or several sheets of paper
  • Stopped by a 3mm hick sheet of aluminium or other metal


  • Weakly ionising
  • Very Penetrating
  • Reduced significantly by a thick lead sheet or blocks of concrete
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Ionising Radiation

Ionising Radiation - Radiation that has enough energy to break molecules or atoms into charged particles called ions.

Ionisation - The molecules or atoms lose electrons

After ionisation the ions can then take part in chemical reactions -> ionising radiation damages living cells.

It kills them / damages their DNA in the cell so that the cells mutates into a cancer cell, which then grows in an uncontrolled manner.

Ionising radiation:

  • Alpha
  • Beta
  • Gamma (from the radioactive nuclei)
  • X-Rays
  • Ultra-Violet Radiation
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We did this today :) Thanks

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