Properties of Radiation (Edexcel GCSE Physics: Combined Science)

• 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

• 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

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

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