# ch38 - Chapter 38 PHOTONS AND MATTER WAVES 1 The units of...

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Unformatted text preview: Chapter 38: PHOTONS AND MATTER WAVES 1. The units of the Planck constant h are those of: A. energy B. power C. momentum D. angular momentum E. frequency ans: D 2. If h is the Planck constant, then ¯ h is: A. 2 π h B. 2 h C. h/ 2 D. h/ 2 π E. 2 h/ π ans: D 3. The quantization of energy, E = nhf , is not important for an ordinary pendulum because: A. the formula applies only to mass-spring oscillators B. the allowed energy levels are too closely spaced C. the allowed energy levels are too widely spaced D. the formula applies only to atoms E. the value of h for a pendulum is too large ans: B 4. The frequency of light beam A is twice that of light beam B. The ratio E A /E B of photon energies is: A. 1 / 2 B. 1 / 4 C. 1 D. 2 E. 4 ans: D 5. The wavelength of light beam B is twice the wavelength of light beam B. The energy of a photon in beam A is: A. half the energy of a photon in beam B B. one-fourth the energy of a photon in beam B C. equal to the energy of a photon in beam B D. twice the energy of a photon in beam B E. four times the energy of a photon in beam B ans: A 574 Chapter 38: PHOTONS AND MATTER WAVES 6. A photon in light beam A has twice the energy of a photon in light beam B. The ratio p A /p B of their momenta is: A. 1 / 2 B. 1 / 4 C. 1 D. 2 E. 4 ans: D 7. Which of the following electromagnetic radiations has photons with the greatest energy? A. blue light B. yellow light C. x rays D. radio waves E. microwaves ans: C 8. Which of the following electromagnetic radiations has photons with the greatest momentum? A. blue light B. yellow light C. x rays D. radio waves E. microwaves ans: C 9. Rank following electromagnetic radiations according to the energies of their photons, from least to greatest. 1. blue light 2. yellow light 3. x rays 4. radio waves A. 1, 2, 3, 4 B. 4, 2, 1, 3 C. 4, 1, 2, 3 D. 3, 2, 1, 4 E. 3, 1, 2, 4 ans: B 10. The intensity of a uniform light beam with a wavelength of 500 nm is 2000 W / m 2 . The photon f ux (in number/m 2 · s) is about: A. 5 × 10 17 B. 5 × 10 19 C. 5 × 10 21 D. 5 × 10 23 E. 5 × 10 25 ans: C Chapter 38: PHOTONS AND MATTER WAVES 575 11. The concentration of photons in a uniform light beam with a wavelength of 500 nm is 1 . 7 × 10 13 m − 3 . The intensity of the beam is: A. 6 . 7 × 10 − 6 W / m 2 B. 1 . × 10 3 W / m 2 C. 2 . × 10 3 W / m 2 D. 4 . × 10 3 W / m 2 E. 3 . 2 × 10 2 W / m 2 ans: C 12. Light beams A and B have the same intensity but the wavelength associated with beam A is longer than that associated with beam B. The photon f ux (number crossing a unit area per unit time) is: A. greater for A than for B B. greater for B than for A C. the same for A and B D. greater for A than for B only if both have short wavelengths E. greater for B than for A only if both have short wavelengths ans: A 13. In a photoelectric e f ect experiment the stopping potential is: A. the energy required to remove an electron from the sample B. the kinetic energy of the most energetic electron ejected C. the potential energy of the most energetic electron ejectedC....
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## This note was uploaded on 04/14/2008 for the course PHYSICS 108 taught by Professor Halstead during the Spring '08 term at SUNY Buffalo.

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ch38 - Chapter 38 PHOTONS AND MATTER WAVES 1 The units of...

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