Properties of Radiation (Edexcel GCSE Physics)

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Comparing Alpha, Beta & Gamma

  • The properties of Alpha, Beta-plus, Beta-minus and Gamma are given in this table, and then described in more detail below

Different Properties of Nuclear Radiation

Radiation Properties Table, downloadable IGCSE & GCSE Physics revision notes
  • The trend down the table shows:
    • The range increases
    • Penetrating power increases
    • Ionisation decreases

Penetrating Power

  • Alpha, beta and gamma have different properties
  • They penetrate materials in different ways
    • This means they are stopped by different materials

penetration increase, IGCSE & GCSE Physics revision notes

Alpha, beta and gamma are different in how they penetrate materials. Alpha is the least penetrating, and gamma is the most penetrating

  • Alpha is stopped by paper, whereas beta and gamma pass through it
  • Beta is stopped by a few millimetres of aluminium
    • Gamma can pass through aluminium

  • Gamma can be reduced by several metres of concrete or several centimetres of lead

  • The more ionising a form of radiation is, the sooner it will react with the air it is moving through
  • Strongly ionising radiation has the shortest range in air
    • Alpha only travels a few centimetres in air
    • Beta has a range of a few tens of centimetres
    • Gamma is not absorbed by air and so has an infinite range, although it does become less intense with distance

Worked example

A student has an unknown radioactive source. They are trying to work which type of radiation is being given off:

A    Alpha particles

   B    Beta particles

   C    Gamma rays

   D    Neutrons

They measure the count-rate, using a Geiger-Muller tube, when the source is placed behind different material. Their results are shown in the table below:

WE Absorption table, downloadable IGCSE & GCSE Physics revision notes

Which type of radiation is being given off by the source?

ANSWER:  B

    • The answer is not A because the radiation passed through the paper almost unchanged
      • This means it is not alpha

    • The answer is not C or D because the aluminium decreased the count-rate significantly
      • This means it is not gamma (gamma penetrates aluminium)
      • This also means it is not neutrons (neutrons penetrate aluminium, however you do not need to know this for your GCSE)

    • Therefore, the source must be Beta particles

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Ashika

Author: Ashika

Expertise: Physics Project Lead

Ashika graduated with a first-class Physics degree from Manchester University and, having worked as a software engineer, focused on Physics education, creating engaging content to help students across all levels. Now an experienced GCSE and A Level Physics and Maths tutor, Ashika helps to grow and improve our Physics resources.