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40 Cards in this Set
- Front
- Back
Natural radioactivity
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the spontaneous emission of particles or energy from an atomic nucleus as it disintegrates
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Alpha particle
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nucleus of a Helium atom, 2 p+ & 2 n0
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Beta particle
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high energy electron
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Gamma ray
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electromagnetic radiation of very short wavelength
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Radioactive decay
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the natural spontaneous disintegration or decomposition of a
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nuclear force
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a strong fundamental force, force of attraction that only works at very short distances
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Protons and neutrons in the nucleus are in moving...
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energy levels, or shells, just as the electrons are - some arrangements are more stable than others.
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Generally… the nucleus is more stable if the protons and neutrons are both
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in even numbers.
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All isotopes with an atomic number greater than...
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83 are unstable.
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Nucleons
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another term for protons and neutrons
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atomic number, determines what element it is
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Number of p+
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can vary, represented as an isotope
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Number of n0
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Radioactive decay allows an unstable nucleus to become...
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more stable with less energy.
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Alpha emission
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the release of an alpha particle from a disintegrating nucleus
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Alpha emission
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can travel 2-12 cm through the air
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Beta emission
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the release of a beta particle from a disintegrating nucleus, this process increases the number of protons in a nucleus
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Beta emission
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a neutron changes to a proton by emitting the electron
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Beta emission
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they are more penetrating and can travel several hundred centimeters in air
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Gamma emission
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the release of a high-energy burst of electromagnetic
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Gamma emission
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this can be caused from the other types of decay, once alpha or beta decay takes place, the nucleus is left in a high-energy state
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Gamma emission
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Nucleons don’t change in this type of emission
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Gamma emission
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most penetrating
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Gamma emission
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can be stopped by a piece of lead close to the source
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Gamma emission
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used to kill many parasites and bacteria in the foods we eat
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Radioactive decay series
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a process continuing through a series of decay reactions until a stable nucleus is achieved
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Half-Life
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the time required for 1/2 of the unstable nuclei to decay
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Instruments for Measuring Radioactivity
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Photographic film & Geiger counters
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Radioactivity can be measured at
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1.) the source of radioactivity & 2.) the place of reception, where radiation is absorbed
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Activity of a source
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a measure of the number of nuclear disintegration per unit of time
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Units for measuring the activity of a source
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curie (Ci) or Becquerel (Bq)
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More specific measurements deal with amount of radiation received by humans is expressed in terms of radiological dose in units of...
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rem.
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A regular person in one day will receive about...
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1 millirem
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Background radiation
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low amounts of radiation from natural sources
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Nuclear fission
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splitting a massive nucleus into more stable, less massive nuclei with the release of energy
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Chain reaction
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a reaction where the products are able to produce more reactions in a self-sustaining series
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Critical mass
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the mass and concentration of nuclei that is sufficient to sustain
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Nuclear fusion
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less massive nuclei coming together to form more stable and
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One problem with developing nuclear fusion
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1.) temperature - nuclei repel one another unless they have enough energy, approximately 100 million °C
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One problem with developing nuclear fusion
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2.) density - heavy hydrogen nuclei needed, 1 x 1014 /cm3
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One problem with developing nuclear fusion
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3.) time - must be sustained at a minimum of 10 atm at this density
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