Lec1

Lec1 - Lecture 1-Quantum Mechanics EE2, Physics of...

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Lecture 1-Quantum Mechanics EE2, Physics of Electrical Engineering UCLA Alex Shailos 1 Wave-particle duality o Waves behaving like particles Photoelectric effect: Waves exhibit particle-like behavior In a metal, a certain amount of energy is required to “free” and electron into the ambient You could turn up intensity low frequency wave all you want and never free an electron o i.e., no proportionality of intensity and frequency, which classical physics asserts o answer: individual units of energy must be arriving. If that unit is below the required energy (no electron is free) ((and it’s very hard for the individual photons to “work together” to free an electron, although it is possible)) E h hf h h 2 h 6.63*10 34 m 2 kg s Waves have momentum! Also, think of energy
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Lecture 1-Quantum Mechanics EE2, Physics of Electrical Engineering UCLA Alex Shailos 2 p hf c h f frequency (1/s) [can also be ] c velocity of light (m/s) c f p momentum h Planck's constant = 6.63x10 34 m 2 kg s h p **I use f instead of for frequency to avoid mixing it with velocity, v** Particles behaving like waves o Why electrons in atoms have certain levels o Used for electron diffraction experiments to determine structure of materials, because electron wavelength is much smaller than optical wavelength (e.g., TEM) p mv m mass {kg} h p h mv p deBroglie wavelength **Remember, c is just a specific velocity, v Electron diffraction experiment o One slit diffraction vs two slit diffraction pattern General equation for a wave o Time dependent Stand at one point and watch the ocean bob o Position dependent Freeze the ocean (stop time) and move along in x t   cos 2 ft x   cos 2 x Combine the two for a traveling wave Show web applet
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Lecture 1-Quantum Mechanics EE2, Physics of Electrical Engineering UCLA Alex Shailos 3 x , t A cos 2 x 2 ft x , t A cos 2 x ft v f x , t A cos 2 x v t A cos 2 x vt 2 k propogation constant (think: spatial frequency) x , t A cos k x vt Another way to write the function. .. x
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This note was uploaded on 02/28/2011 for the course EE 2 taught by Professor Vis during the Winter '07 term at UCLA.

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Lec1 - Lecture 1-Quantum Mechanics EE2, Physics of...

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