Discussion 3

# Discussion 3 - macroscopic matter can be ignored, usually?...

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Chem 20A Discussion 3 Oct. 15 th 2009 TA: Guangye Zhang 1. Photoelectric Effect—Einstein’s solution: E=_____ (1) What is the significance of P.E.E? It overthrew the conception that light is a normal electromagnetic wave, whose energy is continuous and is only proportional to its intensity. (2) The excited electrons’ K.E.=_ ______________________ (3) What is the meaning of ? The minimum energy we need to get electrons coming out from the metal. 2. Wave-Partical Duality (1) How to calculate momentum? For photons P=_______ , For electrons (without relativity effect) P=_=mv____ Also for real particles, K.E=_ _. So, for real particles, ________ (2) Light has _ momentum_____ ________, so we can consider it to be a particle. Light can _ diffract and interfere _ ______, so we can consider it to be a wave. (3) Example: Calculate the wavelength for an electron with a K.E. 100eV. =0.123 nm (4) Why the wave nature of

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Unformatted text preview: macroscopic matter can be ignored, usually? (Take Usain Bolt as an example with a body weight 90 Kg and velocity 10m/s) , no such thin slit can be found. 3. Standing Waves Each mode contains n half-cycles; each mode contains _n-1______ nodes. 4. What experiment first prove the wave nature of a real particle? 1927 C.J Davison and L.H. Germer performed electron diffraction experiment. 5. Borhs Theory , , R==Rydberg Constant Borhs DRIVED the number for R which is based on experiments before! Use the Bohr Model to calculate (1) The radius of the ion in the n=1 state (2) The energy of the ion in the n=1 state ) (3) What frequency of light would be absorbed in a transition from the n=1 to n=2 state of this ion? Atomic number of Lithium: 3 Bohr radius: 1. The ion is a hydrogen-like ion. It has only one electron. Its atomic number (Z) is 3. ,...
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## This note was uploaded on 10/03/2011 for the course CHEM 20A taught by Professor Scerri during the Spring '05 term at UCLA.

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Discussion 3 - macroscopic matter can be ignored, usually?...

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