4994340
Description
Flashcards by Alice Hathaway, updated more than 1 year ago
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Created by Alice Hathaway
about 8 years ago
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| Question | Answer |
| Beta Decay | Nuclei that have too many neutrons. A neutron turns into a proton, causing the element to change. A beta particle is emitted (same as an electron) |
| Alpha Decay | Released by very heavy nuclei e.g. uranium. An alpha particle is a helium nucleus (2 protons/ 2 neutrons) so changes the element when it is emitted. |
| Most to least ionising? | Alpha Beta Gamma |
| Most to least penetrating? | Gamma Beta Alpha |
| Stopped by led, emitted as a ray/ wave, doesn't change the element? | Gamma radiation |
| Stopped by paper, slow moving, changes the element | Alpha radiation |
| Stopped by thin metal, moves quickly, changes the element | Beta radiation |
| Half Life | The time it takes for half of the atom to decay |
| Is the number of neutrons in a element fixed? | No |
| What is an Isotope? | Atoms with the same number of protons but different number of neutrons. E.g. Carbon 12 (6 of each) Carbon 14 ( 6 protons/ 8 neutrons) |
| Describe Rutherford's experiment | Fired alpha particles at thin gold foil |
| What did they see? | Most alpha particles went straight through, but the odd particle bounced straight back |
| What did this show? | Most mass was concentrated in a small nucleus with lost of empty space around it as most went straight through the foil. The nucleus had a positive charge as the positively charges alpha particles were repelled. if it wasn't, they wouldn't have been repelled or scattered. |
| What is the 'strong force'? | The force that holds the nucleus together - stronger than the repulsive electrostatic force between the protons. |
| What is Nuclear Fusion? | Two nuclei that combine to form a heavier and larger nucleus, emitting energy. This requires a lot of energy to get them close enough for the strong force to hold them together. |
| Where can nuclear fusion be found naturally? | In the sun where hydrogen atoms fuse to form helium atoms, releasing lots of energy as heat and light. |
| What is E = MC^2? | Created by Einstein. E= energy M = mass C = speed of light in a vacuum Can calculate the release of energy during nuclear fission or fusion. |
| What is nuclear Fission? | The splitting apart of larger nuclei to make small ones. It releases 2 or three more neutrons and lots of energy. |
| How does nuclear fission work? | A chain reaction is set up. A neutron splits a nucleus which releases more neutrons. These neutrons then continue to split up more nuclei to release more neutrons. |
| What is used for nuclear fission? | Uranium or plutonium fuel rods. |
| How is nuclear fission controlled? | Control rods are used to absorb some of the neutrons to slow down the reaction. They can be moved in and out to absorb more or less. |
| What's done with 'low level' waste? | Buried in secure landfill sites. |
| What is 'low level' waste? | Most waste from power stations (or medical use ); things like paper and gloves |
| What is 'intermediate level' waste? | Quite radioactive and will stay that way for tens of thousands of years. Things like metal cases of fuel rods and some waste from hospitals. |
| What is done with 'intermediate level' waste? | Sealed in concrete blocks and put into steel canisters for storage. |
| What is 'high level' waste? | From nuclear power stations and so reactive that it generates a lot of heat. |
| What is done with 'high level' waste? | Sealed in gas and steel then cooled for 50 years before being moved to permanent storage. |
| Irradiation | Being exposed to radiation without coming in contact with the source. |
| Contamination | Picking up radioactive material, e.g. breathing it in or getting it on your skin |
| What can ionising radiation do to cells? | It can cause mutations that can cause cancer. High doses can kill cells, causing radiation sickness. |
| What is radiation measured in? | Sieverts (Sv) or Millisieverts (mSv) |
| What is background radiation? | Low level radiation that is around all the time. |
| What causes background radiation? | Natural radioactive elements Space Human activity |
| When are radioactive elements considered safe? | When the radiation they emit is the same level as background radiation. |
| What can ionising radiation be used for? | Treating cancer Sterilising medical equipment Sterilising food Detecting disease using trackers |
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