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electron volt definition
the energy required to move an electron through a p.d. of 1V
alpha decay
the emission of a helium nucleus (alpha particle) from an unstable nucleus
beta- decay
the emission of a fast-moving electron and an antineutrino when a neutron turns into a proton
beta+ decay
the emission of a fast-moving positron and a neutrino when a proton turns into a neutron
gamma decay
an excited nucleus de-exciting by emitting a gamma ray
radioactive decay definition
the spontaneous disintegration of a nucleus to form a more stable nucleus, resulting in the emission of an alpha, beta, or gamma particle
activity definition
the number of decays per second, measured in becquerel (nucleus/second)
half-life
the time taken for half the undecayed nuclei to decay or the activity of a source to decay by half
decay constant
represents the probability that an individual nucleus will decay per unit of time
uses of radioactive isotopes
metastable technetium-99 and cobalt60 in medicine
leaks in underground pipes
controlling thickness of materials in factories
carbon-14 dating
americium in smoke detectors
natural sources of background radiation
radon gas from rocks & buildings
cosmic rays
carbon-14 in biological material
artificial sources of background radiation
nuclear medicine
nuclear waste
nuclear weapons & accidents
binding energy definition
the energy required to entirely separate the nucleons of a nucleus
unified atomic mass unit
1/12 the mass of a neutral carbon-12 atom
threshold frequency
the frequency of incident light in which electrons are beginning to be liberated
photoelectric effect definition
the spontaneous emission of electrons from a metal surface when hit by light of a suitable frequency
compton scattering definition
the interaction of a high-energy photon with an orbital electron which causes an increase in the wavelength of the photon and the ejecton of the electron
lyman series
ground state
highest energy photons
shortest wavelength (UV)
pfund series
5th state
lowest energy
longest wavelength (IR)
order of bohr’s hydrogen series
lyman → balmer → ritz-paschen → brackett → pfund
fission definition
the splitting of a large, unstable nucleus into two smaller nuclei
induced fission
thermal neutron + unstable nucleus = 2 smaller nuclei, 1+ neutrons, gamma rays
critical mass definition
the minimum mass of a fuel required to maintain a steady chain reaction
lenz’s law
the current induced by the change in flux will generate a magnetic field to oppose the change
faraday’s law
the induced emf is proportional to the rate of change of magnetic flux linkage
Note 
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