Modern Physics - Nuclear Physics - SS2 Physics Past Questions and Answers - page 3

Alpha radiation consists of helium nuclei, which consist of two protons and two neutrons. It has a positive charge and is relatively heavy compared to other types of radiation. Due to its size and charge, alpha particles have low penetrating power and are easily stopped by a few centimetres of air or a sheet of paper. They have high ionising power and can cause significant damage to living tissues when emitted from a radioactive source.

Beta radiation consists of high-speed electrons or positrons. Beta particles can be negatively charged (electrons) or positively charged (positrons). They have a much smaller mass compared to alpha particles, and therefore, they have greater penetrating power. Beta particles can be deflected by electric and magnetic fields and can travel several metres in the air. They have moderate ionising power and can penetrate into living tissues, causing damage.

The concept of half-life refers to the time it takes for half of the radioactive atoms in a sample to decay. It is a characteristic property of a radioactive isotope. The determination of half-life involves measuring the decay of a radioactive sample over a period of time. By plotting the decay curve and analysing the data, the half-life can be calculated. It signifies the rate at which radioactive decay occurs and provides a measure of the stability or instability of a radioactive material.