Revise GCSE Physics


Question:List the penetrating power and ionising power of the three nuclear radiation in a table.

Radiation Penetration ability Ionisation ability Stopped by
Alpha Least Greatest Paper or 5cm of air
Beta Medium Medium 5 mm of aluminium or 5 meters of air
Gamma Highest Lowest Intensity reduced to 1/2 by metres of lead

Angry face

NB The more penetrating, the less ionising. Ionisation requires energy, the more ionisations that are produced, the more quickly the particle loses energy and the less distance it can travel.

It is a common misconception to believe that alpha particles are relatively harmless because they can be stopped by a piece of paper. However, they have done much more damage to the paper in being stopped than the beta particles did by passing through.