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Published byNatalie McCracken Modified over 11 years ago
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Quantum Physics ….and you thought I couldnt use Powerpoint
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BlackBody Radiation ALL objects radiate thermal energy based on the vibration of the atoms within the molecules Cold in the IR range – not visible Turn up the heat & radiation becomes visible ROYGBIV (red hot toaster or stove burner, white light bulb filament) Big to Short or Low f to high f
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Black-Body Experiment
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Black Body Problem
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Plancks Thinking
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Planck-Thermodynamics Says we get the graphs because atomic oscillators are only able to oscillate at distinct frequencies: E=nhf Compare to a box being pushed up an incline or lifted up individual steps. In the first case the GPE increases continuously in the second in increments. The oscillators produce the em wave.
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Photoelectric Effect (Einsteins Nobel Prize)
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Photoelectric Effect Problem: Wave versus Particle Any f should remove electrons. Not Observed. Intensity Energy Regardless of f Emitted e- energy should depend on Intensity of light beam. Not Observed. Emitted energy depends on f Waves of light spread energy across metal. Requires time for e- to absorb energy and fly off. Not Observed.
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Light & Einstein Einstein: light has no mass, but DOES have KE Einstein predicted light waves have p! Had no way of confirming these formulas Light is a PARTICLE
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E photon =hfKE max =KE electron =work function Stopping Voltage used to find Ke max: U e= KE max KE max =hf-
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Photoelectric Effect Graph y=mx+b Threshold Frequency = x-intercept Work Function = y-intercept Plancks Constant = slope
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