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Unformatted text preview: Instructions Write your name in the given space. For problems 1  2 and 4  16, Circle the correct answer. Problem 3, True or False type. Write True or False for each part. For problems 17  27, Use the given space. Useful values: 1 u = 931 . 5 MeV hc = 1240 nm.eV electron mass = 0 . 511 MeV Planck constant h = 6 . 626 × 10 34 J.s Speed of light c = 3 . × 10 8 m.s 1 Proton mass = 938 . 272 MeV Neutron mass = 939 . 566 MeV u x = u x + v (1 + v u x c 2 ) u x = u x v (1 v u x c 2 ) 1 Name: MP200  Radiation Physics Fall 2010 Test 01 Date: 09/22/2010 ( Show your work for each problem. Partial credits are awarded.) 1. ( 02 points )Which particle has the most kinetic energy? (a) an electron with a total energy of 1000 MeV (b) a proton with a total energy of 1000 MeV (c) a neutron with a total energy of 1500 MeV Solution (a) 2. ( 03 points )If the speed of an electron could be exactly measured, that means that (a) the particle may be located more exactly (b) the particle can not be located at all (c) the uncertainty in its momentum increases (d) the time to measure the position decreases Solution: (b) since Δ p = 0 Δ x = ∞ 3. ( 04 points )True or False: (a) It is impossible in principle to know precisely the position of an electron. Solution: False: the position can be known precisely if the mo mentum is completely undetermined. (b) The Schrodinger equation follows from Newton’s laws of mo tion. 2 Solution: False (c) Boundary conditions on the wave function lead to energy quan tization. Solution: True (d) The expectation value of a quantity is the value that you ex pect to measure. Solution: False: the expectation is the average of the measure ment for a large number of identical systems. It may, or may not, be one of the possible values measured. (e) Characteristic Xrays result from transitions made by inner electrons. Solution: True (f) The “rad” is a measure of the energy deposited per unit volume in matter. Solution: False:It is a measure of the energy deposited per unit mass. (g) In the photoelectric effect, the maximum current is propor tional to the intensity of the incident light. Solution: True (h) In the ground state of the hydrogen atom, the potential energy is 27 . 2 eV . Solution: True 4. ( 03 points )An electron in a hydrogen atom is described by the quantum numbers; n = 8 and m l = 4. What are the possible values for the orbital quantum number l ? (a) only 0 and 4 (b) only 4 or 7 (c) only 5 or 8 (d) only 4, 5, 6, or 7 (e) only 5, 6, 7, or 8 Solution: (d) 5. ( 03 points )A photon source emits photons of 1 . 50 MeV giving a 3 flux density of 2 . 3 × 10 8 photons.cm 2 .sec 1 at a specified location. What is the energy flux density at this location?...
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This note was uploaded on 10/30/2010 for the course MP 200 taught by Professor Guna during the Fall '10 term at Duke.
 Fall '10
 Guna

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