Describe the dangers of ionising radiation in terms of tissue damage and…

The idea

Ionising radiation carries enough energy to remove electrons from atoms, so it can damage living cells. High doses kill cells outright, producing burns or radiation sickness; lower doses may damage DNA, and a cell that survives with altered DNA can divide into mutated cells, which may eventually lead to cancer. Because harm depends on exposure, precautions reduce dose: keep sources shielded (lead or thick concrete), keep distance from the source, limit the time spent near it, store sources in labelled containers, and handle them with tongs so the source stays away from skin. Workers likely to be exposed wear film badges or dosimeters so cumulative dose is monitored. In a multiple-choice question, select the option that links a named danger (tissue damage or mutation) to a matching precaution, and reject options that confuse the danger with the precaution or claim radiation is harmless.

What earns the marks

• Identifies tissue damage, such as cell death, burns or radiation sickness, as a danger of ionising radiation.
• States that ionising radiation can damage DNA and cause mutations that may lead to cancer.
• Links a precaution such as lead shielding, distance, or limiting exposure time to reducing the dose received.
• Rejects an option that treats a precaution as a danger or claims ionising radiation causes no harm to living tissue.

Common mistakes and how to put them right

• Confuses the danger with the precaution.

  Put it right: Keep the two separate, naming tissue damage or mutation as the harm and shielding or distance as the precaution.

• Assumes any exposure is instantly fatal.

  Put it right: Recognise that harm depends on the dose received, so precautions reduce rather than eliminate risk.

• Claims ionising radiation only damages equipment.

  Put it right: State that it damages living tissue and DNA, which is why precautions protect people.

Exam tips

• Read each option and check it names both a real danger and a precaution that logically reduces that danger.
• Eliminate options that describe a precaution as if it were a hazard, or that deny any biological harm.
• Recall that mutations arise from DNA damage in surviving cells, and use that to judge options about long-term effects.