Physics Ch 9. Atomic and Nuclear Phenomena Flashcards
Photoelectric effect
Ejection of an electron from the surface of a metal in response to light, ejected electrons create a current, the magnitude of the skirt is proportional to the intensity of the incident beam of light
Threshold frequency
The minimum light frequency necessary to eject an electron from a given metal
Work function
The minimum energy necessary to eject an electron from a given metal, it’s value depends on the metal used and can be calculated by multiplying the threshold frequency by Planck’s constant, the greater the energy of the incident photon above the work function, the more kinetic energy that checked it electron can possess
Bohr model of the atom
States that electron energy levels are stable and discrete corresponding to specific units, and electron can jump from a lower energy to a higher energy or bowl by absorbing a photon of light of the same frequency as the energy distance between the orbits, when an electron falls from a higher energy to low energy orbit it emits a photon of light of the same frequency as the energy difference between the orbits
Absorption spectra
Baby impacted by small changes in molecular structure
Fluorescence
Occurs when a species absorbs high frequency light and then returns it to its ground state in multiple steps, each step has less energy than the absorbed light and is within the visible range of the electromagnetic spectrum
Nuclear binding energy
The amount of energy that is released when nucleons bind together, the more binding energy per nucleon released, the more stable to nucleus
Nucleons
Protons and neutrons
Four fundamental forces of nature
The strong and weak nucleus force which contribute to the stability of the nucleus, electrostatic forces, and gravitation
Mass effect
The difference between the mass of the unbonded nucleons in the mass of the bond of nucleons within the nucleus, the unbounded constituents have more energy and therefore more mass than the bond and constituents, the mass defect is the amount of mass converted to energy during nuclear fusion
Fusion
Occurs when small nuclei combine into larger nuclei
Fission
Occurs when a large nucleus splits into smaller nuclei
Energy in fission and fusion
Energy is released in both fusion and fission because the nuclei formed in both processes are more stable than the starting nuclei
Radioactive decay
The loss of small particles from the nucleus
Alpha decay
The emission of an alpha particle which is a helium nucleus
Beta negative decay
The decay of a neutron into a proton, with the omission of an electron and an anti-neutrino
Beta positive decay
Also called positron emission, the decay of a proton into a neutron with a mission of a positron and a neutrino
Gamma decay
The emission of a Gamma ray which converts a high energy nucleus into a more stable nucleus
Electron capture
The absorption of an electron from the inner shell that combines with a proton in the nucleus to form a neutron
Half life
The amount of time required for half of a sample of radioactive nuclei to decay
Exponential decay
The rate at which radioactive nuclei decay is proportional to the number of nuclei that remain
Energy of a photon of light equation
E = h*f
Maximum kinetic energy of an electron in the photoelectric effect equation
Kmax = hf-W
Work function equation
W = h*f_t
Mass defect and energy equation
E = mc^2
Rate of nuclear decay equation
deltan/deltat = -lambda*n
Exponential decay equation
n = n_0e^(-lambdat)
Decay constant equation
lambda = ln2/T_(1/2) = 0.693/T_(1/2)
