This introduction covers The Radiation You Can't Escape within Background Radiation for GCSE Physics. Revise Background Radiation in Extra Topics for GCSE Physics with 13 exam-style questions and 12 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 1 of 12 in this topic. Use this introduction to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 1 of 12
Practice
13 questions
Recall
12 flashcards
⚛️ The Radiation You Can't Escape
Right now, as you read this, you are being bombarded with radiation. Cosmic rays from distant exploding stars are passing through you. Radon gas, seeping up from uranium-bearing rocks beneath your feet, is dissolving into your lungs. Potassium-40 in your own bones is spontaneously decaying. Your stone walls, your food and drink, even the air around you — all faintly radioactive.
This is background radiation — the unavoidable, low-level radiation that exists everywhere on Earth. We have evolved with it over billions of years, and at normal background levels it presents a very small risk to health. But it is always there, and physicists must account for it whenever they make any measurement of radioactivity.
In the UK, the average person receives about 2.7 millisieverts (mSv) of radiation dose per year from background sources. This varies enormously depending on where you live — people in Cornwall (which sits on granite rock) receive about twice the UK average because granite is rich in uranium and thorium, which produce radon gas.