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

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Quantum Physics ….and you thought I couldnt use Powerpoint

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

Black-Body Experiment

Black Body Problem

Plancks Thinking

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.

Photoelectric Effect (Einsteins Nobel Prize)

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.

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

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

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