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P2.6.3 - P2.6.4
Types of Radiation
Question | Answer |
---|---|
What does alpha emit? | 2 protons and 2 neutrons |
How do the atomic and mass numbers change after alpha radiation has been emitted? | The atomic number decreases by 2, the mass number decreases by 4 |
Name three features of alpha radiation | Very ionising, Small level of penetration, Can be deflected by a magnetic or electric fields (in the opposite direction to beta) |
Name 3 things that can stop alpha radiation | Skin, 1mm of paper, 5cm of air |
What does beta emit? | A neutron turns into a proton and an electron, the electron is emitted and the proton stays in the nucleus |
How do the atomic and mass numbers change after beta radiation has been emitted | The atomic number increases by 1, the mass number stays the same |
Name three features of beta radiation | Less ionising than alpha, Penetrates further than alpha, Can be deflected by a magnetic or electric fields (in the opposite direction to alpha) |
Name 2 things that can stop beta radiation | 5mm of Aluminium, 1m of Air |
What is gamma radiation? | An electromagnetic wave that is emitted from the nucleus |
How does the nucleus change when gamma radiation is emitted? | It stays the same |
Name three features of gamma radiation | Weakly ionising, Very high penetration Cannot be deflected by a magnetic field |
Name 2 things that can stop gamma radiation | 1m of concrete, 5-7cm of lead |
What is alpha radiation used for? | Smoke alarms. Poorly penetrating particles therefore not dangerous. Needs a half-life of several years |
What is beta radiation used for? | Thickness monitoring - manufacture of paper. Alpha particles would be stopped by a thin sheet of paper and gamma rays would pass straight through it. Needs a half-life of many years so that decreases in count rate are due to the thickness of the paper. |
What is gamma (and beta) radiation used for? | Tracers in medicine. The source is injected or swallowed by the patient. Its progress around the body is monitored by a detector outside the patient's body. Needs a half-life of a few hours so the patient isn't exposed to unnecessary radioactivity. |
What is half-life? | The time taken for the number of unstable nuclei in a sample to halve. |