Flashcards
Radioactivity- Physics
Flashcards do conjunto (24)
- 1Who discovered that electrons could be removed from atoms and suggested the ' plum pudding model'?J.J Thomson in 1897
- 2What happens if an atom loses an electron?It becomes a positive ion
- 3What is ionising radiation?It is any radiation that can knock off electrons from atoms
- 4What are alpha particles stopped by and how far can they travel?They don't penetrate very far. Only travel a few cm in air and are absorbed by a thin sheet of paper.
ARE VERY STRONGLY IONISING - 5What is a beta-minus particle?It is a fast moving electron released by the nucleus .(has no mass and a relative charge of -1)
- 6What is a beta-plus particle?Is a fast moving POSITRON. A positron is the antiparticle of the electron. Exactly the same mass a but has a positive +1 charge instead
- 7What are Gamma rays?They are EM waves with a short wavelength. Penetrate far and travel long distances. ABSORBED by thick sheets of lead or metres of concrete.
- 8Alpha Decay?nucleus loses 2 protons and neutrons so....
the mass number decrases by 4 and atomic number decreases by 2 - 9Beta-minus decay?A neutron changes into a proton and a elctron. Mass number stays the same (as it has lost a neutron but gained a proton)
The atomic number increases by 1 because it has gained one more proton. - 10Beta-plus decay?A proton changes into a neutron and a positron.
Mass number doesn't change howver atomic umber decreases by 1 because it has oe less proton - 11Neutron Emission?Nucleus emits a neutron.
Mass number decreases by 1 as it has lost a neutron but the atomic number stays the same. - 12Gamma RadiationDOES NOT change the charge or mass of the nucleus so atomic/mass number stay the same
- 13radioactive isotopes?Random process which gives out radiation from the nuclei of atoms
- 14Radioactivity of a source?DECREASES over time
- 15What is Half-life?Is the averge time taken for the numbernof radioactive nuclei in an isotope to halve
- 16What does a short half-life suggest?means that the activity falls quickly because nuclei are very unstable and rapidly decay
- 17What does a longer half-life suggest?means the activity falls more slowly because most of the nuclei don't decay for a long time .
Disadvantage- nearby areas exposed to radiationnfor longer - 18Give examples of where background radiation may come from?1.food
2.building materials
3.rocks
4.cosmic rays from space - 19what is exposure to radiation called?Irradation
- 20What is contamination?Is radiaoctive particles getting on the surfaces or within objects
- 21What impact can radiation have living cells?Tissue damage. Lower doses cause uncontrollable mutuation of cells (cancer)
Higher doses kill cells completely , causing radiation sickness - 22Uses of radiation?Alpha= fire alarms
Beta = tracers or to treat health problems
Gamma= sterilise food + equipment - 23What is nuclear FISSION ?the splitting up of big atomic particles
- 24What is nuclear FUSION?Joining small nuclei
Occurs at high temp + pressure
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- GCSE Physics FlashCards sobre Radioactivity- Physics, criado por Disalini Rakuseelan em 28-01-2018.
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- Disalini Rakuseelan
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