physic 2020 chapter 27

42. According to de Broglie, as the momentum of a moving particle is tripled, the corresponding wavelength changes by what factor?

1/3

57. According to Wien's displacement law, if the absolute temperature of a radiating blackbody is tripled, then the peak wavelength emitted will change by what factor?

1/3

58. A sodium vapor lamp has a power output of 300 W. If 590 nm is the average wavelength of the source, about how many photons are emitted per second? (h = 6.63 1034 Js, c = 3.00 108 m/s, and 1 nm = 109 m)

10^21

44. According to Heisenberg, as the uncertainty in the measurement of a particle's momentum is reduced by a factor of 2, by what factor is the uncertainty in that same particle's position changed?

2

72. X-rays of wavelength of 0.065 0 nm undergo Compton scattering from free electrons in carbon. What is the wavelength of photons scattered at 90.0 relative to the incident beam? (h = 6.63 1034 Js, me = 9.11 1031 kg, c = 3.00 108 m/s, and 1 nm = 109 m)

0.067 4 nm

33. Blue light ( = 460 nm) is incident on a piece of potassium ( = 2.20 eV). What is the maximum kinetic energy of the ejected photoelectrons? (h = 6.63 1034 Js, c = 3.00 108 m/s, 1 eV = 1.60 1019 J, and 1 nm = 109 m)

0.50 eV

56. If a quantum of radiation has an energy of 2.0 keV, what is its wavelength? (h = 6.63 1034 Js, 1 eV = 1.60 1019 J, c = 3.00 108 m/s, and 1 nm = 109 m)

0.62 nm

40. What is the de Broglie wavelength for a proton (m = 1.67 1027 kg) moving at a speed of 6.0 106 m/s? (h = 6.63 1034 Js)

0.66 10^-13 m

23. Light of wavelength 450 nm is incident on a target metal that has a work function of 1.80 eV. What stopping potential is required for this combination in a phototube? (h = 6.63 1034 Js, c = 3.00 108 m/s, 1 eV = 1.60 1019 J and 1 nm = 109 m)

0.96 v

20. Starting from rest, an electron accelerates through a potential difference of 40 V. What is its de Broglie wavelength? (h = 6.63 1034 Js, me = 9.11 1031 kg, and 1 eV = 1.60 1019 J)

1.9 1010 m

10. If a blackbody is at 2000 °C, what will be the peak wavelength emitted?

1.27

26. If a monochromatic light beam with quantum energy value of 3.0 eV incident upon a photocell where the work function of the target metal is 1.60 eV, what is the maximum kinetic energy of ejected electrons?

1.4 eV

71. A helium-neon laser emits red light having a wavelength of 632.8 nm and a power of 0.50 mW. How many photons are emitted each second? (h = 6.63 1034 Js, c = 3.00 108 m/s and 1 nm = 109 m)

1.6 1015

67. How much energy (in eV) does a photon of red light ( = 700 nm) have? (h = 6.63 1034 Js, c = 3.00 108 m/s, 1 eV = 1.60 1019 J, and 1 nm = 109 m)

1.78 eV

69. Light of wavelength 480 nm is incident on a metallic surface with a resultant photoelectric stopping potential of 0.55 V. What is the work function of the metal? (h = 6.63 1034 Js, c = 3.00 108 m/s, 1 eV = 1.60 1019 J, and 1 nm = 109 m)

2.04 eV

12. What is the highest frequency of the photons produced by a 90-kV x-ray machine? (h = 6.63 1034 Js)

2.2 10^19 Hz

34. A proton (mass = 1.67 1027 kg) has a kinetic energy of 1.00 MeV. If its momentum is measured with an uncertainty of 1.00%, what is the minimum uncertainty in its position? (h = 6.63 1034 Js, 1 eV = 1.6 1019 J)

2.28 10^-13 m

48. What is the energy of a photon whose frequency is 6.0 1020 Hz? (h = 6.63 1034 Js and 1 eV = 1.60 1019 J)

2.5 MeV

6. In an x-ray diffraction experiment, using x-rays of wavelength = 0.500 1010 m, a first-order maximum occurred at 5.00 off the crystal plane. Find the distance d between crystal planes.

2.87 10^-10 m

52. The spacing between atoms in KCl crystal is 3.1 1010 m. At what angle from the surface will a beam of 3.14 1011 m x-rays be constructively scattered?

2.9

74. If an electron has a measured wavelength of 0.850 1010 m, what is its kinetic energy? (h = 6.63 1034 Js, 1 eV = 1.6 1019 J, and me = 9.11 1031 kg)

209 eV

61. What is the minimum x-ray wavelength produced when electrons are accelerated through a potential of 50 000 V? (h = 6.63 1034 Js, c = 3.00 108 m/s, and 1 eV = 1.60 1019 J)

24.9 1012 m

29. The de Broglie wavelength of a 0.060 kg golf ball is 4.28 1034 m. What is its speed? (h = 6.63 1034 Js)

26 m/s

38. Bragg reflection results in a first-order maximum at 14.2º. In this case, at what angle would the second-order maximum occur?

29.4º

7. An electron microscope operates with electrons of kinetic energy 50.0 keV. What is the wavelength of these electrons? Assume this speed is not relativistic. (h = 6.63 1034 Js, c = 3.00 108 m/s, 1 eV = 1.60 1019 J, and me = 9.11 1031 kg)

5.49 x 10^-12 m

27. Light of wavelength 6.5 107 m has an energy of: (h = 6.63 1034 Js, c = 3.00 108 m/s)

3.1 10^-19 J

19. If the measured momentum of an electron is 3.20 1027 kgm/s with an uncertainty of 1.6 1029 kgm/s, what is the minimum uncertainty in the position? (h = 6.63 1034 Js)

3.3 10^-6 m

64. A monochromatic light beam is incident on a barium target, which has a work function of 2.50 eV. If a stopping potential of 1.0 V is required, what is the light beam photon energy?

3.5 eV

32. What is the energy of a photon that has the same wavelength as a 12-eV electron? (h = 6.63 1034 Js)

3.5 keV

30. Of the following energies for photons, which is the least energy that could result in photoelectron production if the work function is 3.00 eV?

3.50 eV

75. A light beam is shining on a metal target that has a work function of 2.20 eV. If a stopping potential of 1.30 V is required, what is the wavelength of the incoming monochromatic light? (h = 6.63 1034 Js, c = 3.00 108 m/s, 1 eV = 1.60 1019 J and 1 nm = 109 m)

355 nm

62. What is the wavelength of a monochromatic light beam, where the photon energy is 5.00 1019 J? (h = 6.63 1034 Js, c = 3.00 108 m/s, and 1 nm = 109 m)

398 nm

66. A quantum of radiation has an energy of 2.0 keV. What is its frequency? (h = 6.63 1034 Js and 1 eV = 1.60 1019 J)

4.8 1017 Hz

55. In the Compton effect, what is the greatest change in wavelength that can occur? (h = 6.63 10-34 J·s, melectron = 9.11 10-31 kg, c = 3.00 108 m/s)

4.85 10-12 m

76. What is the wavelength of a monochromatic light beam, where the photon energy is 3.00 eV? (h = 6.63 1034 Js, c = 3.00 108 m/s, 1 nm = 109 m, and 1 eV = 1.6 1019 J)

414 nm

73. If barium has a work function of 2.60 eV, what is its cutoff wavelength when used as a phototube target? (h = 6.63 1034 Js, c = 3.00 108 m/s, 1 eV = 1.60 1019 J and 1 nm = 109 m)

478nm

53. What is the energy of a photon with the Compton wavelength (0.002 43 nm)? (h = 6.63 1034 Js, c = 3.00 108 m/s, and 1 eV = 1.60 1019 J)

5.12 105 eV

15. An ultraviolet light beam having a wavelength of 130 nm is incident on a molybdenum surface with work function of 4.2 eV. What is the stopping potential? (h = 6.63 1034 Js, c = 3.00 108 m/s, 1 eV = 1.6 1019 J, and 1 nm = 109 m)

5.4 V

37. What is the surface temperature of a distant star (which emits light as if it were a blackbody) where the peak wavelength is 480 nm? Hint: The surface of the human body at 35 oC has a peak wavelength of 941 m. (1 nm = 109 m = 10-3 m)

6 040 K

8. What is the maximum velocity of a photoelectron emitted from a surface with work function 5.00 eV when illuminated by 200 nm ultraviolet light? (melectron = 9.11 1031 kg, h = 6.63 1034 Js, 1 eV = 1.60 1019 J, and 1 nm = 109 m)

653 000 m/s

13. The "seeing" ability or resolution of radiation is determined by its wavelength. If the size of an atom is approximately 1010 m, how fast must an electron travel to have a wavelength smaller than that of an atom? (me = 9.11 1031 kg, h = 6.63 1034 Js)

7.3 10^6 m/s

2. What is the frequency of monochromatic light where the photon energy is 5.5 1019 J? (h = 6.63 1034 Js)

8.3 ´ 1014 Hz

59. If the minimum x-ray wavelength produced is 13.5 1012 m, through what potential are the electrons accelerated in order to generate this radiation? (h = 6.63 1034 Js, c = 3.00 108 m/s, and 1 eV = 1.60 1019 J)

92 100 V

50. Blue light will not eject electrons from a certain metal; however, which one of the following may possibly eject electrons from that metal?

ultraviolet

65. Which process cannot occur if only one photon is involved?

Compton effect

25. Who was the first to successfully explain the photoelectric effect?

Einstein

45. The uncertainty principle was derived by whom?

Heisenberg

28. Who conceived the idea of using a crystal for observing diffraction of x-rays?

von Laue

21. Which of the following statements best describes the relation between the quantum theory and the photoelectric effect experiment?

Quantum theory explains the photoelectric effect

47. Star A has the peak of its blackbody radiation at A. Star B has its peak at B which is one fourth that of A. If Star A's surface temperature is TA, how does the surface temperature TB of Star B compare?

TB = 4 TA

60. That light has a dual nature is referring to light:

acting as waves and particles

1. The ultraviolet catastrophe predicts that:

all objects should radiate extreme amounts of ultraviolet light.

36. Planck's quantum theory is compatible with the experimental data related to which of the following?

all of the above

9. Classical theories predict that most of the energy from a black body should be radiated:

as ultraviolet light

22. Which change will not change the kinetic energy of the most energetic electrons emitted in the photoelectric effect?

changing the brightness of the light

51. As the temperature of a radiation emitting blackbody becomes higher, what happens to the peak wavelength of the radiation?

decreases

18. An important use of x-ray diffraction was:

determining the structure of the DNA molecule

68. X-ray production occurs in which process?

electrons hitting a metal, emitting photons

35. The Heisenberg uncertainty principle places restriction on the precision of simultaneously measuring both position and momentum. This principle can also be applied to the simultaneous measurement of two other variables, which are:

energy and time interval

14. In Bragg's law, 2d sin = m, how is measured?

from the reflecting crystal plane

24. A photon absorbed by an electron will give up more energy to the electron if the photon:

has a higher frequency

41. The electron microscope's main advantage over the optical microscope is which of the following?

higher resolution possible

16. In regard to the Compton scattering experiment with x-rays incident upon a carbon block, as the scattering angle becomes larger, what happens to the magnitude of difference between the incident and scattered wavelengths?

increases

5. According to Einstein, what is true of the stopping potential for a photoelectric current as the wavelength of incident light becomes shorter?

increases

70. According to the de Broglie hypothesis, which of the following statements is applicable to the wavelength of a moving particle?

inversely proportional to its momentum

49. If an x-ray machine were designed to operate at two separate accelerating voltages, one double the other, how would the shortest wavelength, min, hv, and the maximum frequency, fmax, hv, at the higher voltage compare to those (min, lv, fmax, lv) at the lower voltage?

min, hv/ min, lv = ____, fmax, hv/ fmax, lv =____: 1/2, 2

31. The Compton experiment demonstrated which of the following when an x-ray photon collides with an electron?

momentum and energy are both conserved

3. Which of the following devices represent(s) a practical application of the photoelectric effect?

photocell

54. The wave function as derived in Schrödinger's equation is best described as being a measure of which of the following?

probability is referring to light: acting as waves and particles

46. According to Einstein, as the wavelength of the incident monochromatic light beam becomes shorter, the work function of a target material in a phototube:

remains constant

43. Due to the dual nature of light and matter, either can act in an experiment as if it is a wave or a particle. In which experiment is the wave aspect exhibited for matter?

the Davisson and Germer experiment

17. According to Einstein, increasing the brightness of a beam of light without changing its color will increase:

the number of photons

63. Rosalind Franklin was:

the producer of the x-ray diffraction photographs that led to the DNA structure

11. Sources of red, blue, and yellow light each emit light with a power of 50 mW. Which source emits more photons per second?

the red source

4. Changing the accelerating voltage of an x-ray machine without changing the target material must change:

the wavelength of the minimum wavelength x-ray that will be produced.

39. Of the following photons, which has the highest energy?

ultraviolet