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30 Cards in this Set
- Front
- Back
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Rutherford
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Conducted scattering experiments by firing subatomic particles at atoms in order to ascertain that the atom is composed of a dense nucleus with tiny orbitting electrons.
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John Dalton
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Used the law of definite proportions to argue for the existance of atoms.
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J.J. Thompson
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Discovered the electron. Argued that electrons must be contained inside atoms.
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Kinetic Theory
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The description of the macroscopic properties of atoms.
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Temperature
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A measure of energy per atom.
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Mean free path
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The average distance that a molecule travels between collisions.
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Brownian motion
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tiny particles suspended in any fuild exhibit erratic motion.
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Milikan's oil drop experiment
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Suspended oil droplets in electric field in order to determine the value of the charge on an individual electron. Could hold a particle constant when the upward electrical force was equal to the force of gravity.
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Photons
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quanta of light
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Max Planck
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First person to propose that electromagnetic radiation must be quantized. h is planck's constant.
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Lorentz force
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The force on each electron in fields E and B
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Photoelectric effect
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Discovered by Hertz, a metal exposed to light is found to eject electrons from its surface.
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Stopping Potential
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V when all current ceases. Not enough enough V to overcome retarding potential
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Work function
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for any metal, the definite minimum energy to remove and elction.
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Arthur Compton
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His observations of the scattering of electromagnetic radiation by atoms showed clearly that photons should be regarded as particles.
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W. L. Bragg
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Used crystals as X-ray diffraction gratings. Theta=theta (prime).
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Bragg Law
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2dsin(theta)=nlamda
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Characteristic X-rays
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the x-ray spikes which occur at certain frequencies.
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Compton effect
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The American physicist Arthur Holly Compton explained the wavelength increase when high frequency X-rays were scattered off electrons by considering X-rays as composed of discrete pulses, or quanta, of electromagnetic energy
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Niels Bohr
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Devised a model of the hydrogen atom, that , while not complete, was a major stepping stone to quantum mechanics.
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Moseley
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Showed that the wavelengths of X-rays emitted by atoms depend on the atomic number exactly as predicted by the Bohr model.
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Elastic collision
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total KE conserved
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Franck-Hertz Experiment
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Was a physics experiment that provided support for the Bohr model of the atom.Stream of electrons passed through a tube of mercury vapor.There is a grid in front on an anode. The elctrons that pass through the grid and have enough energy to overcome the retarding force will reach anode. Shows quantized energy levels.
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De Broglie's Hypothesis
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Proposed material particles should also show a wave particle duality.
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Wave function
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The mathematical function that specifies the wave disturbance at each point of space and time.
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Sinusoidal Waves
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A wave with definite frequency and wavelength. Stretches infinitely.
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Amplitude
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Maximum displacement of the string from its mean position.
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Wave Packet
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Type of wave function localized in some region.
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Fourier analysis
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the study of the composition of functions as sums of sinusoidal waves.
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Heisenberg Uncertainty relationship
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Can't know the position and momentum of a particle. Choose one.
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