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- 1why do the nuclei of radioactive atoms emit radiationthe nuclei are unstable, so they emit radiation to become more stable, this is called radioactive decay
- 2give the definition and unit of activityin becquerel (Bq), the rate at which a source of unstable nuclei decay
- 3what is the count-rate and how is it measuredthe number of decays recorded each second by a detector eg Geiger-Muller tube
- 4give examples and define different types of nuclear radiationalpha particle
beta particle
gamma ray - 5alpha particlehelium nuclei, two neutrons and two protons. Alpha radiation is when alpha particles are emitted from the nucleus, they can't pass more than a few cm's in the air and be stopped by a sheet of paper. Strongly ionising.
- 6beta particlesfast moving electron, released by the nucleus, virtually no mass. Has a charge of -1. Moderately ionising, can be stopped by a sheet of aluminium. For every beta particle emitted. A neutron in the nucleus turns into a proton
- 7gamma rayselectromagnetic waves released by the nucleus. They are weakly ionising, can travel far in air but can be stopped by thick sheets of led or metres of concrete
- 8radius of an atom and nucleus1x10*-10 metres
1/10000 of the radius of an atom - 9where is most of the mass of an atom concentratedthe nucleus
- 10what can happen to the electron arrangement with the absorption of electromagnetic radiation or by the emission of em radiationthe absorption can lead to electrons movinG further away from the nucleus to higher energy level and vice versa for emitting
- 11where can you find the mass number and atomic number in the element in the periodic tablethe top and the bottom
- 12whats an isotopeatoms of the same element with different number of neutrons
- 13whats the plum pudding modelit suggested that the atom is a ball of positive charge with negative electrons embedded in it
- 14what was concluded from the results of the alpha particle scattering experimentmass of the atom is concentrated at the centre of the atom, which was charged. this nuclear model replaced the plum pudding model
- 15what did Niels Bohr discoverthat electrons orbit the nucleus at specific distances
- 16what did james chadwick discoverthe existence of neutrons in the nucleus
- 17give how alpha particles are represented in a nuclear equation
- 18give how beta particles are represented in a nuclear equation
- 19alpha decay causes both the ____ and the ____ of the nucleus to decreasemass
charge - 20beta decay makes the ____ of the nucleus to increasecharge
- 21true or false, radioactive decay is randomtrue
- 22what is a half-lifehalf-life of a radioactive isotope is the time it takes for the number of nuclei of the isotope in a sample to half or the time taken for the count-rate/ activity to half
- 23where does background radiation come fromrocks and cosmic rays from space (our atmosphere protects us from most of it), fallout from nuclear weapon testing and nuclear accidents (eg ur birth), also it can come from the air, food or building materials
- 24true or false, the level of background radiation is not affected by occupation or locationfalse
- 25what is radiation measured in?Sv (Sieverts)
- 26give uses of nuclear radiation in medicineexploration of internal organs, control/ destruction of unwanted tissue eg radiotherapy, medical traces for gamma rays
- 27definition of Irradiationwhen an object is exposed to a radioactive source, doesn't become radioactive
- 28give advantages and disadvantages for using radiation for medical treatmentgamma traces can be used to diagnose life threatening conditions, but they give a small increased risk of CANCER. Prolonged exposure to radiation can cause many risks and damage normal cells, gamma rays can be used to kill cancer cells.
- 29definition of nuclear fissionthe splitting of a large unstable nucleus
- 30Spontaneous fission is ___, usually for fission to occur the unstable nucleus must first absorb a ___. The nucleus undergoing fission splits into ___ smaller nuclei and emits two or three neutrons plus ____ _____. Energy is released and the neutrons may go on to make a chain reaction.rare
neutron
two
gamma rays - 31nuclear fusion definitionthe joining of two light nuclei from a heavier nucleus, some of the mass may be converted into the energy of radiation
- 32radioactive contaminationthe unwanted presence of radioactive materials
- 33the hazard from contamination is due to the ____ of the containing atomsdecay
- 34the ___ radiation affects the level og hazardtype
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- GCSE (paper 1) Physics Fichas sobre Sin título, creado por lizabeth rawson el 08/02/2020.
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- lizabeth rawson · feb 2020
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- 8 feb 2020
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