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1 第 1 頁, 共 8 頁 Chap32&Chap33 1. Test Bank, Question 2 Gauss' law for magnetism tells us: the net charge in any given volume that the line integral of a magnetic around any closed loop must vanish the magnetic of a current element that magnetic monopoles do not exist charges must be moving to produce magnetic s 2. *Chapter 32, Problem 3 A Gaussian surface in the shape of a right circular cylinder with end caps has a radius of 14.1 cm and a length of 98.7 cm. Through one end there is an inward magnetic flux of 32.9 μwb. At the other end there is a uniform magnetic of 2.12 mt, normal to the surface and directed outward. What is the magnitude of the net magnetic flux through the curved surface? Number Units µwb Significant digits are disabled; the tolerance is +/-2% 3. Test Bank, Question 8 Suppose you are looking into one end of a long cylindrical tube in which there is a uniform electric, pointing away from you. If the magnitude of the is decreasing with time the direction of the induced magnetic is: toward you away from you clockwise counterclockwise to your right 4. Test Bank, Question 18 Maxwell's great contribution to electromagnetic theory was his hypothesis that: work is required to move a magnetic pole through a closed path surrounding a current a time-varying electric flux acts as a current for purposes of producing a magnetic the speed of light could be determined from simple electrostatic and magnetostatic experiments (finding the values of 0 and )

第 2 頁, 共 8 頁 the magnetic force on a moving charge particle is perpendicular to both magnetism could be explained in terms of circulating currents in atoms 5.

2 第 2 頁, 共 8 頁 the magnetic force on a moving charge particle is perpendicular to both magnetism could be explained in terms of circulating currents in atoms 5. *Chapter 32, Problem 10 In an electric is directed out of the page within a circular region of radius R = 4.00 cm. The magnitude of the electric is given by E = (0.900 V/m s)(1 - r/r)t, where radial distance r R and t is in seconds. What is the magnitude of the magnetic that is induced at radial distances (a)3.00 cm and (b)6.00 cm? (a) Number E-20 (b) Number E-20 Units T Units T 6. Test Bank, Question 26 Consider the four Maxwell equations: I. II. III. IV. Which of these must be modified if magnetic poles are discovered? only I only II only II and III

3 第 3 頁, 共 8 頁 only III and IV only II, III, IV 7. Test Bank, Question 55 If is the orbital angular momentum of an electron, the magnetic dipole moment associated with its orbital motion: is in the direction of and has magnitude proportional to L is opposite to the direction of and has magnitude proportional to L is in the direction of and has magnitude proportional to L 2 is opposite to the direction of and has magnitude proportional to L 2 does not depend on 8. Test Bank, Question 58 The intrinsic magnetic dipole moments of protons and neutrons are much less than that of an electron because: their masses are greater their angular momenta are much less their angular momenta are much greater their charges are much less their radii are much less 9. Test Bank, Question 65 A magnetic is applied to a diamagnetic substance. In the interior the magnetic produced by the magnetic dipoles of the substance is:

4 第 4 頁, 共 8 頁 greater than and in the opposite direction less than and in the opposite direction greater than and in the same direction less than and in the same direction the same as 10. Test Bank, Question 70 The diagram shows two small paramagnetic shperes, one near each end of a bar magnet. Which of the following statements is true? The forces on 1 and 2 are both away from the magnet The forces on 1 and 2 are both toward the magnet The force on 1 is toward the magnet and the force on 2 is away from the magnet The force on 1 is away from the magnet and the force on 2 is away from the magnet The magnet does not exert a force on either sphere 11. Test Bank, Question 78 Because ferromagnets exhibit hysteresis, the magnetization: can never be in the same direction as an applied may not vanish when an applied is reduced to zero can never vanish is proportional to any applied magnetic is always opposite to the direction of any applied magnetic 12. Test Bank, Question 12

5 第 5 頁, 共 8 頁 Which of the following types of electromagnetic radiation travels at the greatest speed in vacuum? Radio waves Visible light X rays Gamma rays All of these travel at the same speed 13. Test Bank, Question 16 Radio waves of wavelength 3 cm have a frequency of: 1 MHz 9 MHz 100 MHz 10,000 MHz 900 MHz 14. Test Bank, Question 7 Maxwell's equations predict that the speed of electromagnetic waves in free space is given by: 15. Test Bank, Question 18 If the electric in a plane electromagnetic wave is given by E m sin[( /m 1 )x t)], in SI the value of is: 0.01 rad/s 10 rad/s 100 rad/s

6 第 6 頁, 共 8 頁 rad/s rad/s 16. Test Bank, Question 20 The electric for a plane electromagnetic wave traveling in the +y direction is shown. Consider a point where is in the +z direction. The is: in the +x direction and in phase with the in the x direction and in phase with the in the +x direction and 1/4 wave out of phase with the in the +z direction and in phase with the in the +z direction and 1/4 wave out of phase with the 17. *Chapter 33, Problem 73 The electric component of a beam of polarized light is E y = (5.10 V/m) sin[( m -1 )z + ωt]. (a) Write an expression for the magnetic component of the wave, including a value for ω. What are the (b) wavelength, (c) period, and (d) intensity of this light? (e) Parallel to which axis does the magnetic oscillate? (f) In which region of the electromagnetic spectrum is this wave? (a)b x = ( nt) sin[( /m)z + ( E+14 1/s)t] (b) Number Units micron (c) Number Units fs (d) Number Units mw/m^2 (e) x (f) infrared

7 第 7 頁, 共 8 頁 18. *Chapter 33, Problem 17 The maximum electric 13 m from a point light source is 3.0 V/m. What are (a) the maximum value of the magnetic and (b) the average intensity of the light there? (c) What is the power of the source? (a) E-8 T (b) W/m^2 (c) Number Units W 19. *Chapter 33, Problem 27 A plane electromagnetic wave, with wavelength 3.9 m, travels in vacuum in the positive direction of an x axis. The electric, of amplitude 450 V/m, oscillates parallel to the y axis. What are the (a) frequency, (b) angular frequency, and (c) angular wave number of the wave? (d) What is the amplitude of the magnetic component? (e) What is the time-averaged rate of energy flow associated with this wave? The wave uniformly illuminates a surface of area 2.0 m 2. If the surface totally absorbs the wave, what are (f) the rate at which momentum is transferred to the surface and (g) the radiation pressure? (a) Hz (b) Number Units rad/s (c) Number Units rad/m or m^-1 (d) T (e) W/m^2 (f) Number Units N (g) Number E-7 Units N/m^2 or Pa 20. *Chapter 33, Problem 33 In Fig , initially unpolarized light is sent into a system of three polarizing sheets whose polarizing directions make angles of θ 1 = 31, θ 2 = 20, and θ 3 = 41 with the direction of the y axis. What percentage of the light's initial intensity is transmitted by the system? Figure Number Units percent

第 8 頁, 共 8 頁 Significant digits are disabled; the tolerance is +/-2% 21. *Chapter 33, Problem 65 Figure 33-61 depicts a simplistic optical fiber: a plastic core (n 1 = 1.

The rays is to undergo total internal reflection at point A, where it encounters the core-sheath boundary. (Thus there is no loss of light through that boundary.

8 第 8 頁, 共 8 頁 Significant digits are disabled; the tolerance is +/-2% 21. *Chapter 33, Problem 65 Figure depicts a simplistic optical fiber: a plastic core (n 1 = 1.60) is surrounded by a plastic sheath (n 2 = 1.46). A light ray is incident on one end of the fiber at angle θ. The rays is to undergo total internal reflection at point A, where it encounters the core-sheath boundary. (Thus there is no loss of light through that boundary.) What is the maximum value of θ that allows total internal reflection at A? Number Units (degrees) Significant digits are disabled; the tolerance is +/-2% 22. *Chapter 33, Problem 70 In Fig , a light ray in air is incident on a flat layer of material 2 that has an index of refraction n 2 = 2.6. Beneath material 2 is material 3 with an index of refraction n 3. The ray is incident on the air material 2 interface at the Brewster angle for that interface. The ray of light refracted into material 3 happens to be incident on the material 2 material 3 interface at the Brewster angle for that interface. What is the value of n 3? Number 1 Units This answer has no units Significant digits are disabled; the tolerance is +/-2%

Chapter 33: ELECTROMAGNETIC WAVES 559

Chapter 33: ELECTROMAGNETIC WAVES 1 Select the correct statement: A ultraviolet light has a longer wavelength than infrared B blue light has a higher frequency than x rays C radio waves have higher frequency