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# class20 - An single electron bashes into an atom in a...

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An single electron bashes into an atom in a discharge lamp 10 V If atom fixed at this point in tube, -10eV -6 eV -3 eV -2 eV + - If atom fixed at this point in tube, list all the possible photon energies (colors) that you might see? A. 1eV, 2eV, 3eV, 4eV, 7eV, 8eV B. 4eV, 7eV, 8eV C. 1eV, 3eV, 4eV D. 4eV E. Impossible to tell. An single electron bashes into an atom in a discharge lamp 10 V If atom fixed at this point in tube, -10eV -6 eV -3 eV -2 eV D d + - list all the possible photon energies (colors) that you might see? A. 1eV, 2eV, 3eV, 4eV, 7eV, 8eV B. 4eV, 7eV, 8eV C. 1eV, 3eV, 4eV D. 4eV E. Impossible to tell. Answer is D. Electron only gains about 5eV! Electron energy = q V = e(Ed), where E is the electric field = (battery V)/(total distance D), and d is the distance it goes before a collision. Remember the ‘Electron Volt’ (eV)? Define new energy unit: The electron-volt (eV) 1eV = kinetic energy gained/lost by an electron when accelerated/decelerated by traversing an area with 1 Volt potential difference (such as in a plate capacitor) E F 0V 1V path + + + + 1eV 1.6 ·10 -19 J Some handy relations: 1 Ampere = 1 Coulomb / Second 1 Watt = 1 Ampere · 1 Volt = 1 C/s · 1 V Current flowing through a wire:

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## This note was uploaded on 08/24/2010 for the course PHYS 2130 taught by Professor Staff during the Spring '08 term at Colorado.

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class20 - An single electron bashes into an atom in a...

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