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Quantum Physics ….and you thought I couldnt use Powerpoint.

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Presentation on theme: "Quantum Physics ….and you thought I couldnt use Powerpoint."— Presentation transcript:

1 Quantum Physics ….and you thought I couldnt use Powerpoint

2 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

3 Black-Body Experiment

4 Black Body Problem

5 Plancks Thinking

6 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.

7 Photoelectric Effect (Einsteins Nobel Prize)

8 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.

9 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

10 E photon =hfKE max =KE electron =work function Stopping Voltage used to find Ke max: U e= KE max KE max =hf-

11 Photoelectric Effect Graph y=mx+b Threshold Frequency = x-intercept Work Function = y-intercept Plancks Constant = slope

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