CAIE Physics - Nuclear physics

What is meant by the binding energy of a nucleus?
[2 marks]

Energy required to separate nucleons to infinity

Define mass defect [2 marks]

difference between mass of nucleus and (total) mass of nucleons

when infinitely separated

What is meant by nuclear fusion?

The process in which two light nuclei join together to form a heavier nucleus

What is meant by nuclear fission?

 The process in which a massive nucleus splits into two smaller nuclei

What is meant by the term “activity”?

The rate of decay of nuclei of a radioactive source. The unit of activity is the becquerel, Bq.

Define the decay constant.

The probability that an individual nucleus will decay per unit time interval.

What is meant by spontaneous decay?

Decay is not affected by external factors

What is meant by random decay?

Cannot predict when a particular nucleus will decay.

What is meant by radioactive decay? [3 marks]

When an unstable nucleus, spontaneously emits radioactive particles that are ionising.

Define the atomic mass unit, u.

1/12 of the mass of a neutral atom of carbon-12.