Physics 6C Final Practice

Physics 6C Final Practice - Physics 6C Final Practice...

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Physics 6C Final Practice Questions clas.ucsb.edu/staff/vince/ Use the following information for problems 1 and 2. A beam of white light with frequency between 4.00 x 10 14 Hz and 7.90 x 10 14 Hz is incident on a sodium surface, which has a work function of 2.28 eV. 1) What is the range of frequencies in this beam of light for which electrons are ejected from the sodium surface? a) 4.00 x 10 14 Hz to 7.90 x 10 14 Hz b) 4.00 x 10 14 Hz to 6.44 x 10 14 Hz c) 5.10 x 10 14 Hz to 7.90 x 10 14 Hz d) 5.50 x 10 14 Hz to 7.90 x 10 14 Hz 2) What is the maximum kinetic energy of the photoelectrons that are ejected from this surface? a) 9.96 x 10 -20 J b) 1.59 x 10 -19 J c) 2.65 x 10 -19 J d) 5.24 x 10 -19 J 3) When light of a particular wavelength and intensity shines on the surface of a given metal, no electrons are ejected. Which of the following changes will most likely cause the emission of photoelectrons? a) Decreasing the frequency of the light b) Increasing the intensity of the light c) Decreasing the wavelength of the light d) Increasing the wavelength of the light 4) What is the de Broglie wavelength for a Helium atom (atomic mass=4.002603 u) traveling at a speed of 10 3 m/s? Use the conversion factor 1 u = 1.66054 x 10 -27 kg. a) 4.0 x 10 -11 m b 1.0 x 10 -10 m c) 6.2 x 10 6 m d) 2.5 x 10 -12 m 5) The position of an electron is measured with uncertainty 1x10 -6 m. What is the minimum uncertainty in the electron’s velocity? Use electron mass = 9.11x10 -31 kg. a)
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This note was uploaded on 09/09/2011 for the course PHYSICS 6c taught by Professor Staff during the Spring '11 term at UCSB.

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Physics 6C Final Practice - Physics 6C Final Practice...

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