hw6 solution

# hw6 solution - . As the particles have the same velocity,...

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PHYS126 HW6 Solution 1. Solution A. By using B. Inverse the equation to get When n =2, When n =3, For n>3, , the solution does not exist. 2. Solution A. As the object is a blackbody, assume all the energy and momentum of photon are absorbed perfectly Total energy absorbed: Momentum absorbed: B. By momentum conservation, C. Most energy is conversed to heat. 3. Solution From the de Broglie wavelength equation: Since the mass of proton is much larger than that of electron, the de Broglie wavelength of electron is much longer than that of proton. The group velocity is same as the particle’s velocity, as given by the question; proton and electron have the same energy. For phase velocity, it is given by

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Unformatted text preview: . As the particles have the same velocity, they also have the same phase velocity. 4. Solution A. For photon: , For electron: From , B. From ,if energy is much higher than , then the equation is reduced to , so 5. Solution 1 The longest possible wavelength is . Momentum: By using Solution 2 (from previous year) Since the electron is supposed to be confined within the region, By uncertainty principle, Which mean the magnitude of p must be, on average , of this order. Then the kinetic energy is For reference , by particle in a box model, 6. Solution Length of group Number of wave Approx. min bandwidth is 12.5 MHz...
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## This note was uploaded on 03/31/2011 for the course PHY 126 taught by Professor Hobunchan during the Spring '11 term at HKUST.

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hw6 solution - . As the particles have the same velocity,...

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