Explain why nuclear radiation from a radioactive source can be described as ionising radiation, and state one danger this poses to living cells.

WJEC GCSE Physics (Wales) — 2.9 Nuclear decay and nuclear energy · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Radioactive substances emit radiation that can travel through materials and interact with matter. This radiation is described as ionising radiation.

Model answer (4 marks)

Ionising radiation has sufficient energy to remove electrons from atoms or molecules, producing charged particles called ions.
This ionisation can damage or break DNA strands in living cells.
Such damage can cause mutations that may lead to cancer, or it can kill cells outright.

Examiner tips

Use the term ‘ionising radiation’ and explain energy removal of electrons. Show the link between ionisation and DNA damage. Mention a specific danger such as cancer or cell death. Keep answer concise and use correct terminology.

Common mistakes

Using ‘non‑ionising’ or ‘low‑energy’ to describe the radiation. Failing to mention the removal of electrons or the creation of ions. Giving a vague or unrelated danger instead of DNA damage or cancer.

Mark scheme (4 marks)

Ionising radiation has enough energy to remove electrons from atoms/molecules
This creates charged particles called ions
Ionising radiation can damage or break DNA in living cells
This can cause mutations leading to cancer, or kill cells outright

Key terms in this question

ionising radiation · ion