1. Late at night and without IRB approval, Ronnie would often enter the nursery and conduct experiments in static electricity.

2. Mother and daughter are both enjoying the effects of electrically charging their bodies. Each individual hair on their heads becomes charged and exerts a repulsive force on the other hairs, resulting in the “stand-up’’ hairdos that you see here. (Courtesy of Resonance Research Corporation)
Fig 23CO, p.707

3. Figure 23.2 When a glass rod is rubbed with silk, electrons are transferred from the glass to the silk. Because of conservation of
charge, each electron adds negative charge to the silk, and an equal positive charge is left behind on the rod. Also, because the charges are transferred in discrete bundles, the charges on the two objects are +/-e, or +/-2e, or +/-3e, and so on.
Fig 23-2, p.708

4. Figure 23.3 (Quick Quiz 23.1) rubbing a balloon against your hair on a dry day causes the balloon and your hair to become charged. Charles D. Winters
Fig 23-3, p.709

5. Figure 23.5 (b) A charged comb attracts bits of paper because charges in molecules in the paper are realigned.
Fig 23-5b, p.710

6. Figure 23.5 (a) The charged object on the left induces a charge distribution on the surface of an insulator due to realignment of charges in the molecules.
Fig 23-5a, p.710

7. Figure 23.5 (a) The charged object on the left induces a charge distribution on the surface of an insulator due to realignment of charges in the molecules.

8. Figure 23.5 (a) The charged object on the left induces a charge distribution on the surface of an insulator due to realignment of charges in the molecules.

9. Figure 23.1 (a) A negatively charged rubber rod suspended by a thread is attracted
to a positively charged glass rod. (b) A negatively charged rubber rod is repelled by
another negatively charged rubber rod.
Fig 23-1, p.708

10. Figure 23.1 (a) A negatively charged rubber rod suspended by a thread is attracted
to a positively charged glass rod.
Fig 23-1a, p.708

11. Figure 23.1 (b) A negatively charged rubber rod is repelled by
another negatively charged rubber rod.
Fig 23-1b, p.708

12. Figure 23.4 Charging a metallic object by induction (that is, the two objects never touch each other). (a) A neutral metallic sphere, with equal numbers of positive and negative charges. (b) The electrons on the neutral sphere are redistributed when a charged rubber rod is placed near the sphere. (c) When the sphere is grounded, some of its electrons leave through the ground wire. (d) When the ground connection is removed, the sphere has excess positive charge that is nonuniformly distributed. (e) When the rod is removed, the remaining electrons redistribute uniformly and there is a net uniform distribution of positive charge on the sphere.
Fig 23-4, p.710

13. Figure 23.4 Charging a metallic object by induction (that is, the two objects never touch each other). (a) A neutral metallic sphere, with equal numbers of positive and negative charges.
Fig 23-4a, p.710

14. Figure 23.4 Charging a metallic object by induction (that is, the two objects never touch each other). (b) The electrons on the neutral sphere are redistributed when a charged rubber rod is placed near the sphere.
Fig 23-4b, p.710

15. Figure 23.4 Charging a metallic object by induction (that is, the two objects never touch each other). (c) When the sphere is grounded, some of its electrons leave through the ground wire.
Fig 23-4c, p.710

16. Figure 23.4 Charging a metallic object by induction (that is, the two objects never touch each other). (d) When the ground connection is removed, the sphere has excess positive charge that is nonuniformly distributed.
Fig 23-4d, p.710

17. Figure 23.4 Charging a metallic object by induction (that is, the two objects never touch each other). (e) When the rod is removed, the remaining electrons redistribute uniformly and there is a net uniform distribution of positive charge on the sphere.
Fig 23-4e, p.710

18. Figure 23.6 Coulomb’s torsion balance, used to establish the inverse-square law for the electric force between two charges.
Fig 23-6 p.711

19. p.712 or a proton (e) and has a magnitude e 1.602 19 10 19 C (23.5)
Therefore, 1 C of charge is approximately equal to the charge of electrons
or protons. This number is very small when compared with the number of free
electrons in 1 cm 3 of copper, which is on the order of Still, 1 C is a substantial
amount of charge. In typical experiments in which a rubber or glass rod is charged by
friction, a net charge on the order of 10 6 C is obtained. In other words, only a very
small fraction of the total available charge is transferred between the rod and the
rubbing material.
Charles Coulomb French physicist (1736–1806)
Coulomb’s major contributions to science were in the areas of electrostatics and magnetism. During his lifetime, he also investigated the strengths of materials and determined the forces that affect objects on beams, thereby contributing to the field of structural mechanics. In the field of ergonomics, his research provided a fundamental understanding of the ways in which people and animals can best do work. (Photo courtesy of AIP Niels Bohr Library/E. Scott Barr Collection)
p.712

20. Table 23-2, p.717

21. Table 23-1, p.712

22. Figure 23. 8 (Example 23. 2) The force exerted by q1 on q3 is F13
Figure 23.8 (Example 23.2) The force exerted by q1 on q3 is F13. The force exerted by q2 on q3 is F23. The resultant force F3 exerted on q3 is the vector sum F13 F23.
Fig 23-8, p.713

23. Figure (Example 23.5) The total electric field E at P equals the vector sum E1 + E2, where E1 is the field due to the positive charge q 1 and E2 is the field due to the negative charge q2.
Fig 23-14, p.718

24. Figure 23. 21 The electric field lines for a point charge
Figure The electric field lines for a point charge. (a) For a positive point charge, the lines are directed radially outward. (b) For a negative point charge, the lines are directed radially inward. Note that the figures show only those field lines that lie in the
plane of the page. (c) The dark areas are small pieces of thread suspended in oil, which align with the electric field produced by a small charged conductor at the center.
Fig 23-21ab, p.724

25. Figure 23. 21 The electric field lines for a point charge
Figure The electric field lines for a point charge. (a) For a positive point charge, the lines are directed radially outward. (b) For a negative point charge, the lines are directed radially inward. Note that the figures show only those field lines that lie in the
plane of the page. (c) The dark areas are small pieces of thread suspended in oil, which align with the electric field produced by a small charged conductor at the center.
Fig 23-21ab, p.724

26. Figure 23. 21 The electric field lines for a point charge
Figure The electric field lines for a point charge. (c) The dark areas are small pieces of thread suspended in oil, which align with the electric field produced by a small charged conductor at the center.
Fig 23-21c, p.724

27. Figure (a) The electric field lines for two point charges of equal magnitude and opposite sign (an electric dipole). The number of lines leaving the positive charge equals the number terminating at the negative charge. (b) The dark lines are small
pieces of thread suspended in oil, which align with the electric field of a dipole.
Fig 23-22a, p.724

28. Figure (b) The dark lines are small pieces of thread suspended in oil, which align with the electric field of a dipole.
Fig 23-22b, p.724

29. Figure (a) The electric field lines for two positive point charges. (The locations A, B, and C are discussed in Quick Quiz 23.7.)
Fig 23-23a, p.725

30. Figure (b) Pieces of thread suspended in oil, which align with the electric field created by two equal-magnitude positive charges. Courtesy of Harold M. Waage, Princeton University
Fig 23-23b, p.725

31. Active Figure The electric field lines for a point charge +2q and a second point charge -q. Note that two lines leave +2q for
every one that terminates on -q.
Fig 23-24, p.725

32. Figure The electric field at P due to a continuous charge distribution is the vector sum of the fields E due to all the elements q of he charge distribution.
Fig 23-16, p.719

33. Figure (Example 23.7) The electric field at P due to a uniformly charged rod lying along the x axis. The magnitude of the field at P due to the segment of charge dq is kedq/x 2 . The total field at P is the vector sum over all segments of the rod.
Fig 23-17, p.721

34. This dramatic photograph captures a lightning bolt striking a tree near some rural homes. Lightning is associated with very strong electric fields in the atmosphere.
p.716

35. Figure 23. 27 Schematic diagram of a cathode ray tube
Figure Schematic diagram of a cathode ray tube. Electrons leaving the cathode C are accelerated to the anode A. In addition to accelerating electrons, the electron gun is also used to focus the beam of electrons, and the plates deflect the beam.
Fig 23-27, p.728

36. E
(x, y)
Figure An electron is projected horizontally into a uniform electric field produced by two charged plates. The electron undergoes a downward acceleration (opposite E), and its motion is parabolic while it is between the plates.
Fig 23-26, p.726

37. Figure 23.9 (Example 23.3) Three point charges are placed along the x axis. If the resultant force acting on q3 is zero, then the force F13 exerted by q1 on q3 must be equal in magnitude and opposite in direction to the force F23 exerted by q2 on q3.
Fig 23-9, p.714

38. Figure (Example 23.4) (a) Two identical spheres, each carrying the same charge q, suspended in equilibrium. (b) The
free-body diagram for the sphere on the left.
Fig 23-10, p.715

39. Figure (Example 23.4) (a) Two identical spheres, each carrying the same charge q, suspended in equilibrium.
Fig 23-10a, p.715

40. Figure 23.10 (Example 23.4) (b) The free-body diagram for the sphere on the left.
Fig 23-10b, p.715

41. Figure A small positive test charge q0 placed near an object carrying a much larger positive charge Q experiences an electric field E directed as shown.
Fig 23-11, p.716

42. Figure (Example 23.6) The total electric field E at P due to two charges of equal magnitude and opposite sign (an electric dipole) equals the vector sum E1 + E2. The field E1 is due to the positive charge q, and E2 is the field due to the negative charge q.
Fig 23-15, p.719

43. Figure 23. 18 (Example 23. 8) A uniformly charged ring of radius a
Figure (Example 23.8) A uniformly charged ring of radius a. (a) The field at P on the x axis due to an element of charge dq. (b) The total electric field at P is along the x axis. The perpendicular component of the field at P due to segment 1 is canceled by the perpendicular component due to segment 2.
Fig 23-18, p.722

44. Figure 23. 18 (Example 23. 8) A uniformly charged ring of radius a
Figure (Example 23.8) A uniformly charged ring of radius a. (a) The field at P on the x axis due to an element of charge dq.
Fig 23-18a, p.722

45. Figure 23. 18 (Example 23. 8) A uniformly charged ring of radius a
Figure (Example 23.8) A uniformly charged ring of radius a. (b) The total electric field at P is along the x axis. The perpendicular component of the field at P due to segment 1 is canceled by the perpendicular component due to segment 2.
Fig 23-18b, p.722

46. Figure 23. 19 (Example 23. 9) A uniformly charged disk of radius R
Figure (Example 23.9) A uniformly charged disk of radius R. The electric field at an axial point P is directed along the central axis, perpendicular to the plane of the disk.
Fig 23-19, p.722

47. Figure 23. 20 Electric field lines penetrating two surfaces
Figure Electric field lines penetrating two surfaces. The magnitude of the field is greater on surface A than on surface B.
Fig 23-20, p.723

48. Figure (Example 23.10) A positive point charge q in a uniform electric field E undergoes constant acceleration in the direction of the field.
Fig 23-25, p.726

49. Fig P23-7, p.731

50. Fig P23-10, p.731

51. Fig P23-12, p.731

52. Fig P23-15, p.731

53. Fig P23-19, p.732

54. Fig P23-21, p.732

55. Fig P23-22, p.732

56. Fig P23-34, p.733

57. Fig P23-35, p.733

58. Fig P23-40, p.733

59. Fig P23-41, p.734

60. Fig P23-49, p.734

61. Fig P23-52, p.734

62. Fig P23-53, p.735

63. Fig P23-54, p.735

64. Fig P23-55, p.735

65. Fig P23-59, p.736

66. Fig P23-61, p.736

67. Fig P23-62, p.736

68. Fig P23-66, p.737

69. Fig P23-68, p.737

70. Fig P23-73, p.738