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| Question | Answer |
| What is a radioactive substance? | A radio substance contains unstable nuclei that become stable by emitting radiation. |
| What three types if radiations are given out from a radioactive substance? | Alpha,beta and gamma radiation. |
| When does a radioactive source give out radiation(radiation decay)? | We cannot predict or influence when it will happen. |
| Where does background radiation come form? | It comes from radioactive substances in the environment or from space or from devices such as X-ray machines. |
| Why was the plum pudding model of the atom rejected? | Because it could not explain why some alpha particles were scattered through large angles. |
| What is an isotope? | An element with the same number of protons but different numbers of neutrons. |
| How far can each type of radiation travel in air? | It has a range of a few cetimetres in air. |
| How can we separate a beam of alpha, beta and gamma radiation? | By using a magnetic or an electric field. |
| Why are alpha, beta and gamma radiation dangerous? | Alpha, beta and gamma radiation ionise substances they pass through. Ionisation in a living cell can damage or kill the cell. |
| What do we mean by the 'half-life' of a radioactive source? | It is the average time it takes for the number of nuclei of the isotope in a sample to halve. |
| What do we mean by the activity of a radioactive source? | It is the number of nuclei that decay per second. |
| What happens to the activity of a radioactive isotopes as it decays? | The number of atoms of a radioactive isotope and the activity both decrease by half ever half-life. |
| How do we choose a radioactive isotopes for a particular job? | It depends on its half-life and the type of radiation it gives out. |
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