123Aex3verAsol - Name _Student ID _ Score_ last first I....

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Name ___________________________________ Student ID ____________ Score_______ last first Physics 123A, Spring 09, Version A Exam 3, page 1 I. Matter Waves A beam of neutrons (rest mass 1 . 675 × 10 -27 kg) of kinetic energy 7 . 54 × 10 -15 J strikes a target that contains a single slit. Assume that the slit is very small (sub- atomic-sized) dimension in the horizontal width, but macroscopic (about 2 mm) in the vertical dimension. 1. (5 pts) Which choice best represents the deBroglie wavelength of these neutrons? 2 . 62 × 10 7 m 5 . 03 × 10 -21 m 1 . 32 × 10 -13 m 1 . 87 × 10 -13 m 3 . 82 × 10 -13 m A B C D E 2. (5 pts) Which choice best represents a physics law or principle that could be used to explain why a neutron does not just follow a straight path through the slit to the screen? A. Conservation of Energy. B. Heisenberg Uncertainty Principle. C. Stefan-Boltzmann Radiation Law. D. Planck’s Quantization Principle. E. Conservation of Angular Momentum. Useful Data: h = 6 . 63 × 10 -34 J s 1 . 000 eV = 1 . 602 × 10 -19 J ' Incoming neutrons Target with slit Screen Pattern on screen White = many neutrons
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Name ___________________________________ Student ID ____________ Score_______ last first Physics 123A, Spring 09, Version A Exam 3, page 2 II. Photons When electromagnetic radiation of wavelength λ = 348 nm strikes a metal plate, the maximum kinetic energy of ejected electrons is found to be 1 . 80 eV. 3. (4 pts) Which choice best represents the frequency f of the incident radiation? 4 . 31x10 14 Hz 8 . 62x10 14 Hz 7 . 63x10 14 Hz 9 . 43x10 14 Hz 1 . 16x10 -15 Hz A B C D E 4. (4 pts) Which choice best represents the value of the work function for this metal? 1 . 77 eV 1 . 80 eV 2 . 10 eV 3 . 57 eV 3 . 90 eV A B C D E 5. (4 pts) Which choice best represents the maximum kinetic energy of electrons that could be ejected from this metal plate using light of frequency f = 4 . 61 × 10 14 Hz? 0 . 108 eV
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123Aex3verAsol - Name _Student ID _ Score_ last first I....

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