Chapter #22 Solutions - University Physics with Modern Physics Volume 2 (Chapters 21-40) - Gary Westfall, Wolfgang Bauer - 2nd Edition

1cc. Which of the charges in the figure is (are) positive?...a) 1b) 2c) 3d) 1 and 3e) All three charges are positive. Get solution

1mcq. In order to use Gauss’s Law to calculate the electric field created by a known distribution of charge, which of the following must be true?a) The charge distribution must be in a nonconducting medium.b) The charge distribution must be in a conducting medium.c) The charge distribution must have spherical or cylindrical symmetry.d) The charge distribution must be uniform.e) The charge distribution must have a high degree of symmetry that allows assumptions about the symmetry of its electric field to be made. Get solution

2cc. Assuming that there are no charges in the four regions shown in the figure, which of the patterns could represent an electric field?............a) only 1b) only 2c) 2 and 3d) 1 and 4e) None of the patterns represent an electric field. Get solution

2mcq. An electric dipole consists of two equal and opposite charges situated a small distance from each other. When the dipole is placed in a uniform electric field, which of the following statements is (are) true?a) The dipole will not experience any net force from the electric field; since the charges are equal and have opposite signs, the individual effects will cancel out.b) There will be no net force and no net torque acting on the dipole.c) There will be a net force but no net torque acting on the dipole.d) There will be no net force, but there will (in general) be a net torque acting on dipole. Get solution

3cc. An electrically neutral dipole is placed in an external electric field as shown in the figure. In which situation(s) is the net force on the dipole zero?......a) 1 and 3b) 2 and 4c) 1 and 4d) 2 and 3e) 1 only Get solution

3mcq. A point charge, +Q, is located on the x-axis at x = a, and a second point charge, –Q, is located on the x-axis at x = –a. A Gaussian surface with radius r = 2a is centered at the origin. The flux through this Gaussian surface isa) zero.b) greater than zero.c) less than zero.d) none of the above. Get solution

4cc. An electrically neutral dipole is placed in an external electric field as shown in the figure in Concept Check 22.3. In which situation(s) is the net torque on the dipole zero?a) 1 and 3b) 2 and 4c) 1 and 4d) 2 and 3e) 1 only Get solution

4mcq. A charge of +2q is placed at the center of an uncharged conducting shell. What will be the charges on the inner and outer surfaces of the shell, respectively?a) –2q, +2qb) –q, +qc) –2q, –2qd) –2q, +4q Get solution

5mcq. Two infinite nonconducting plates are parallel to each other, with a distance d = 10.0 cm between them, as shown in the figure. Each plate carries a uniform charge distribution of σ = 4.5 µC/m2. What is the electric field, ..., at point P (with xP = 20.0 cm)?...a) 0 N/Cb) 2.54... N/Cc) (–5.08·105)... N/Cd) (5.08·105)... N/Ce) (–1.02·106)... N/Cf) (1.02·106)... N/C Get solution

6cc. A small positively charged object could be placed in a uniform electric field at position A or position B in the figure. How do the electric forces on the object at the two positions compare?...a) The magnitude of the electric force on the object is greater at position A.b) The magnitude of the electric force on the object is greater at position B.c) There is no electric force on the object at either position A or position B.d) The electric force on the object at position A has the same magnitude as the force on the object at position B but is in the opposite direction.e) The electric force on the object at position A is the same nonzero electric force as that on the object at position B. Get solution

6mcq. At which of the following locations is the electric field the strongest?a) a point 1 m from a 1-C point chargeb) a point 1 m (perpendicular distance) from the center of a 1-m-long wire with 1 C of charge distributed on itc) a point 1 m (perpendicular distance) from the center of a 1-m2 sheet of charge with 1 C of charge distributed on itd) a point 1 m from the surface of a charged spherical shell with a radius of 1 me) a point 1 m from the surface of a charged spherical shell with a radius of 0.5 m and a charge of 1 C Get solution

7cc. A negative charge –q is placed in a nonuniform electric field as shown in the figure. What is the direction of the electric force on this negative charge?...a) ...b) ...c) ...d) ...e) The force is zero. Get solution

8cc. A cylinder made of an insulating material is placed in an electric field as shown in the figure. The net electric flux passing through the surface of the cylinder is...a) positive.b) negative.c) zero. Get solution

8mcq. A single positive point charge, q, is at one corner of a cube with sides of length L, as shown in the figure. The net electric flux through the three adjacent sides is zero. The net electric flux through each of the other three sides is...a) q/3ε0.b) q/6 ε0.c) q/24 ε0.d) q/8 ε0. Get solution

9cc. The lines in the figure are electric field lines, and the circle is a Gaussian surface. For which case(s) is (are) the total electric flux nonzero?......a) 1 onlyb) 2 onlyc) 4, 5, and 6d) 6 onlye) 1 and 2 Get solution

9mcq. Three –9-mC point charges are located at (0,0), (3 m,3 m), and (3 m,–3 m). What is the magnitude of the electric field at (3 m,0)?a) 0.9·107 N/Cb) 1.2·107 N/Cc) 1.8·107 N/Cd) 2.4·107 N/Ce) 3.6·107 N/Cf) 5.4·107 N/Cg) 10.8·107 N/C Get solution

10cc. A hollow, conducting sphere is initially given an evenly distributed negative charge. A positive charge +q is brought near the sphere and placed at rest as shown in the figure. What is the direction of the electric field inside the hollow sphere?...a) ...b) ...c) ...d) ...e) The field is zero. Get solution

10mcq. Which of the following statements is (are) true?a) There will be no change in the charge on the inner surface of a hollow conducting sphere if additional charge is placed on the outer surface.b) There will be some change in the charge on the inner surface of a hollow conducting sphere if additional charge is placed on the outer surface.c) There will be no change in the charge on the inner surface of a hollow conducting sphere if additional charge is placed at the center of the sphere.d) There will be some change in the charge on the inner surface of a hollow conducting sphere if additional charge is placed at the center of the sphere.... Get solution

11cc. A hollow, conducting sphere is initially uncharged. A positive charge, +q1, is placed inside the sphere, as shown in the figure. Then, a second positive charge, +q2, is placed near the sphere but outside it. Which of the following statements describes the net electric force on each charge?...a) There is a net electric force on +q2 but not on +q1.b) There is a net electric force on +q1 but not on +q2.c) Both charges are acted on by a net electric force with the same magnitude and in the same direction.d) Both charges are acted on by a net electric force with the same magnitude but in opposite directions.e) There is no net electric force on either charge. Get solution

11mcq. What are the signs of the charges in the configuration shown in the figure?a) Charges 1, 2, and 3 are negative.b) Charges 1, 2, and 3 are positive.c) Charges 1 and 3 are positive, and 2 is negative.d) Charges 1 and 3 are negative, and 2 is positive.e) All that can be said is that the charges have the same sign. Get solution

12cc. A total of 1.45 · 106 excess electrons are placed on an initially electrically neutral wire of length 1.13 m. What is the magnitude of the electric field at a point at a perpendicular distance of 0.401 m away from the center of wire? (Hint: Assume that 1.13 m is close enough to “infinitely long.”)a) 9.21 · 10–3 N/Cb) 2.92 · 10–1 N/Cc) 6.77 · 101 N/Cd) 8.12 · 102 N/Ce) 3.31 · 103 N/C Get solution

12mcq. Which of the following statements is (are) true?a) Electric field lines point inward toward negative charges.b) Electric field lines form circles around positive charges.c) Electric field lines may cross.d) Electric field lines point outward from positive charges.e) A positive point charge released from rest will initially accelerate along a tangent to the electric field line at that point. Get solution

13cc. Suppose an uncharged solid steel ball, for example, one of the steel balls used in an old-fashioned pinball machine, is resting on a perfect insulator. Some small amount of negative charge (say, a few hundred electrons) is placed at the north pole of the ball. If you could check the distribution of the charge after a few seconds, what would you detect?a) All of the added charge has vanished, and the ball is again electrically neutral.b) All of the added charge has moved to the center of the ball.c) All of the added charge is distributed uniformly over the surface of the ball.d) The added charge is still located at or very near the north pole of the ball.e) The added charge is performing a simple harmonic oscillation on a straight line between the south and north poles of the ball. Get solution

13cq. Many people have been sitting in a car when it was struck by lightning. Why were they able to survive such an experience? Get solution

14cc. Suppose an uncharged hollow sphere made of a perfect insulator, for example a ping-pong ball, is resting on a perfect insulator. Some small amount of negative charge (say, a few hundred electrons) is placed at the north pole of the sphere. If you could check the distribution of the charge after a few seconds, what would you detect?a) All of the added charge has vanished, and the sphere is again electrically neutral.b) All of the added charge has moved to the center of the sphere.c) All of the added charge is distributed uniformly over the surface of the sphere.d) The added charge is still located at or very near the north pole of the sphere.e) The added charge is performing a simple harmonic oscillation on a straight line between the south and north poles of the sphere. Get solution

14cq. Why is it a bad idea to stand under a tree in a thunderstorm? What should one do instead to avoid getting struck by lightning? Get solution

15cq. Why do electric field lines never cross? Get solution

16cq. How is it possible that the flux through a closed surface does not depend on where inside the surface the charge is located (that is, the charge can be moved around inside the surface with no effect whatsoever on the flux)? If the charge is moved from just inside to just outside the surface, the flux changes discontinuously to zero, according to Gauss’s Law. Does this really happen? Explain. Get solution

17cq. A solid conducting sphere of radius r1 has a total charge of +3Q. It is placed inside (and concentric with) a conducting spherical shell of inner radius r2 and outer radius r3. Find the electric field in these regions: r r1, r1 r r2, r2 r r3, and r > r3. Get solution

18cq. A thin rod has end points at x = ± 100 cm. There is a total charge Q uniformly distributed along the rod.a) What is the electric field very close to the midpoint of the rod?b) What is the electric field a few centimeters (perpendicularly) from the midpoint of the rod?c) What is the electric field very far (perpendicularly) from the midpoint of the rod? Get solution

19cq. A dipole is completely enclosed by a spherical surface. Describe how the total electric flux through this surface varies with the strength of the dipole. Get solution

20cq. Repeat Example 22.3, assuming that the charge distribution is –λ for –a x λ for 0 x a.Example 22.3 Finite Line of Charge...... Get solution

22cq. Saint Elmo’s fire is an eerie glow that appears at the tips of masts and yardarms of sailing ships in stormy weather and at the tips and edges of the wings of aircraft in flight. St. Elmo’s fire is an electrical phenomenon. Explain it, concisely. Get solution

23cq. A charge placed on a conductor of any shape forms a layer on the outer surface of the conductor. Mutual repulsion of the individual charge elements creates an outward pressure on this layer, called electrostatic stress. Treating the infinitesimal charge elements like tiles of a mosaic, calculate the magnitude of this electrostatic stress in terms of the surface charge density, σ. Note that σ need not be uniform over the surface. Get solution

24cq. An electric dipole is placed in a uniform electric field as shown in the figure. What motion will the dipole have in the electric field? Which way will it move? Which way will it rotate?... Get solution

25. A point charge, q = 4.00 · 10–9 C, is placed on the x-axis at the origin. What is the electric field produced at x = 25.0 cm? Get solution

26. A +1.60-nC point charge is placed at one corner of a square (1.00 m on a side), and a –2.40-nC charge is placed on the corner diagonally opposite. What is the magnitude of the electric field at either of the other two corners? Get solution

27. A +48.00-nC point charge is placed on the x-axis at x = 4.000 m, and a –24.00-nC point charge is placed on the y-axis at y = –6.000 m. What is the direction of the electric field at the origin? Get solution

28. Two point charges are placed at two of the corners of a triangle as shown in the figure. Find the magnitude and the direction of the electric field at the third corner of the triangle.... Get solution

29. A +5.00-C charge is located at the origin. A –3.00-C charge is placed at x = 1.00 m. At what finite distance(s) along the x-axis will the electric field be equal to zero? Get solution

30. Three charges are on the y-axis. Two of the charges, each –q, are located y = ± d, and the third charge, +2q, is located at y = 0. Derive an expression for the electric field at a point P on the x-axis. Get solution

31. For the electric dipole shown in the figure, express the magnitude of the resulting electric field as a function of the perpendicular distance x from the center of the dipole axis. Comment on what the magnitude is when x >> d.... Get solution

32. Consider an electric dipole on the x-axis and centered at the origin. At a distance h along the positive x-axis, the magnitude of electric field due to the electric dipole is given by k(2qd)/h3. Find a distance perpendicular to the x-axis and measured from the origin at which the magnitude of the electric field is the same. Get solution

36. Two uniformly charged insulating rods are bent in a semicircular shape with radius r = 10.0 cm. If they are positioned so that they form a circle but do not touch and if they have opposite charges of +1.00 µC and –1.00 µC, find the magnitude and the direction of the electric field at the center of the composite circular charge configuration. Get solution

35. A thin glass rod is bent into a semicircle of radius R. A charge +Q is uniformly distributed along the upper half, and a charge –Q is uniformly distributed along the lower half as shown in the figure. Find the magnitude and direction of the electric field ... (in component form) at point P, the center of the semicircle.... Get solution

37. A uniformly charged rod of length L with total charge Q lies along the y-axis, from y = 0 to y = L. Find an expression for the electric field at the point (d,0) (that is, the point at x = d on the x-axis). Get solution

38. A charge Q is distributed evenly on a wire bent into an arc of radius R, as shown in the figure. What is the electric field at the center of the arc as a function of the angle θ? Sketch a graph of the electric field as a function of θ for 0 θ ... Get solution

39. A thin, flat washer is a disk with an outer diameter of 10.0 cm and a hole of diameter 4.00 cm in the center. The washer has a uniform charge distribution and a total charge of 7.00 nC. What is the electric field on the axis of the washer at a distance of 30.0 cm from the center of the washer? Get solution

40. Research suggests that the electric fields in some thunderstorm clouds can be on the order of 10.0 kN/C. Calculate the magnitude of the electric force acting on a particle with two excess electrons in the presence of a 10.0-kN/C field. Get solution

41. An electric dipole has opposite charges of 5.00·10–15 C separated by a distance of 0.400 mm. It is oriented at 60.0° with respect to a uniform electric field of magnitude 2.00·103 N/C. Determine the magnitude of the torque exerted on the dipole by the electric field. Get solution

42. Electric dipole moments of molecules are often measured in debyes (D), where 1 D = 3.34·10–30 C m. For instance, the dipole moment of hydrogen chloride gas molecules is 1.05 D. Calculate the maximum torque such a molecule can experience in the presence of an electric field of magnitude 160.0 N/C. Get solution

43. An electron is observed traveling at a speed of 27.5·106 m/s parallel to an electric field of magnitude 11,400 N/C. How far will the electron travel before coming to a stop? Get solution

44. Two charges, +e and –e, are a distance of 0.680 nm apart in an electric field, E, that has a magnitude of 4.40 kN/C and is directed at an angle of 45.0° with respect to the dipole axis. Calculate the dipole moment and thus the torque on the dipole in the electric field. Get solution

45. A body of mass M, carrying charge Q, falls from rest from a height h (above the ground) near the surface of the Earth, where the gravitational acceleration is g and there is an electric field with a constant component E in the vertical direction.a) Find an expression for the speed, v, of the body when it reaches the ground, in terms of M, Q, h, g, and E.b) The expression from part (a) is not meaningful for certain values of M, g, Q, and E. Explain what happens in such cases. Get solution

47. A total of 3.05·106 electrons are placed on an initially uncharged wire of length 1.33 m.a) What is the magnitude of the electric field a perpendicular distance of 0.401 m away from the midpoint of the wire?b) What is the magnitude of the acceleration of a proton placed at that point in space?c) In which direction does the electric field force point in this case? Get solution

48. Four charges are placed in three-dimensional space. The charges have magnitudes +3q, –q, +2q, and –7q. If a Gaussian surface encloses all the charges, what will be the electric flux through that surface? Get solution

49. The six faces of a cubical box each measure 20.0 cm by 20.0 cm, and the faces are numbered such that faces 1 and 6 are opposite to each other, as are faces 2 and 5, and faces 3 and 4. The flux through each face is given in the table. Find the net charge inside the cube.... Get solution

50. A conducting solid sphere (R = 0.15 m, q = 6.1·10–6 C) is shown in the figure. Using Gauss’s Law and two different Gaussian surfaces, determine the electric field (magnitude and direction) at point A, which is 0.0000010 m outside the conducting sphere. (Hint: One Gaussian surface is a sphere, and the other is a small right cylinder.)... Get solution

51. Electric fields of varying magnitudes are directed either inward or outward at right angles on the faces of a cube, as shown in the figure. What is the strength and direction of the field on the face F?... Get solution

52. Consider a hollow spherical conductor with total charge +5e. The outer and inner radii are a and b, respectively.(a) Calculate the charge on the sphere’s inner and outer surfaces if a charge of –3e is placed at the center of the sphere.(b) What is the total net charge of the sphere? Get solution

54. A hollow conducting spherical shell has an inner radius of 8.00 cm and an outer radius of 10.0 cm. The electric field at the inner surface of the shell, Ei, has a magnitude of 80.0 N/C and points toward the center of the sphere, and the electric field at the outer surface, Eo, has a magnitude of 80.0 N/C and points away from the center of the sphere (see the figure). Determine the magnitude of the charge on the inner surface and on the outer surface of the spherical shell.... Get solution

55. A –6.00-nC point charge is located at the center of a conducting spherical shell. The shell has an inner radius of 2.00 m, an outer radius of 4.00 m, and a charge of +7.00 nC.a) What is the electric field at r = 1.00 m?b) What is the electric field at r = 3.00 m?c) What is the electric field at r = 5.00 m?d) What is the surface charge distribution, σ, on the outside surface of the shell? Get solution

56. A solid, nonconducting sphere of radius a has total charge Q and a uniform charge distribution. Using Gauss’s Law, determine the electric field (as a vector) in the regions r a and r > a in terms of Q. Get solution

57. There is an electric field of magnitude 150.0 N/C, directed downward, near the surface of the Earth. What is the net electric charge on the Earth? You can treat the Earth as a spherical conductor of radius 6371 km. Get solution

58. A hollow metal sphere has inner and outer radii of 20.0 cm and 30.0 cm, respectively. As shown in the figure, a solid metal sphere of radius 10.0 cm is located at the center of the hollow sphere. The electric field at a point P, a distance of 15.0 cm from the center, is found to be E1 = 1.00 ·104 N/C, directed radially inward. At point Q, a distance of 35.0 cm from the center, the electric field is found to be E2 = 1.00 ·104 N/C, directed radially outward. Determine the total charge on(a) the surface of the inner sphere,(b) the inner surface of the hollow sphere, and (c) the outer surface of the hollow sphere.... Get solution

59. Two parallel, infinite, nonconducting plates are 10.0 cm apart and have charge distributions of +1.00 µC/m2 and –1.00 µC/m2. What is the force on an electron in the space between the plates? What is the force on an electron located outside the two plates near the surface of one of the two plates? Get solution

60. An infinitely long charged wire produces an electric field of magnitude 1.23·103 N/C at a distance of 50.0 cm perpendicular to the wire. The direction of the electric field is toward the wire.a) What is the charge distribution?b) How many electrons per unit length are on the wire? Get solution

61. A solid sphere of radius R has a nonuniform charge distribution ρ = Ar2, where A is a constant. Determine the total charge, Q, within the volume of the sphere. Get solution

62. Two parallel, uniformly charged, infinitely long wires are 6.00 cm apart and carry opposite charges with a linear charge density of λ = 1.00 µC/m. What are the magnitude and the direction of the electric field at a point midway between the two wires and 40.0 cm above the plane containing them? Get solution

63. A sphere centered at the origin has a volume charge distribution of 120. nC/cm3 and a radius of 12.0 cm. The sphere is centered inside a conducting spherical shell with an inner radius of 30.0 cm and an outer radius of 50.0 cm. The charge on the spherical shell is –2.00 mC. What are the magnitude and the direction of the electric field at each of the following distances from the origin?a) at r = 10.0 cmb) at r = 20.0 cmc) at r = 40.0 cmd) at r = 80.0 cm Get solution

64. A thin, hollow, metal cylinder of radius R has a surface charge distribution σ. A long, thin wire with a linear charge density λ/2 runs through the center of the cylinder. Find an expression for the electric field and determine the direction of the field at each of the following locations:a) r ≤ Rb) r ≥ R Get solution

65. Two infinite sheets of charge are separated by 10.0 cm as shown in the figure. Sheet 1 has a surface charge distribution of σ1 = 3.00 µC/m2 and sheet 2 has a surface charge distribution of σ 2 = –5.00 µC/m2. Find the total electric field (magnitude and direction) at each of the following locations:a) at point P, 6.00 cm to the left of sheet 1b) at point P', 6.00 cm to the right of sheet 1... Get solution

66. A conducting solid sphere of radius 20.0 cm is located with its center at the origin of a three-dimensional coordinate system. A charge of 0.271 nC is placed on the sphere.a) What is the magnitude of the electric field at point (x,y,z) = (23.1 cm,1.10 cm,0.00 cm)?b) What is the angle of this electric field with the x-axis at this point?c) What is the magnitude of the electric field at point (x,y,z) = (4.10 cm,1.10 cm,0.00 cm)? Get solution

67. A solid nonconducting sphere of radius a has a total charge +Q uniformly distributed throughout its volume. The surface of the sphere is coated with a very thin (negligible thickness) conducting layer of gold. A total charge of –2Q is placed on this conducting layer. Use Gauss’s Law to do the following.a) Find the electric field E(r) for r a (inside the sphere, up to and excluding the gold layer).b) Find the electric field E(r) for r > a (outside the coated sphere, beyond the sphere and the gold layer).c) Sketch the graph of E(r) versus r. Comment on the continuity or discontinuity of the electric field, and relate this to the surface charge distribution on the gold layer.... Get solution

68. A solid nonconducting sphere has a volume charge distribution given by ρ(r) = (β/r) sin(πr/2R). Find the total charge contained in the spherical volume and the electric field in the regions r R and r > R. Show that the two expressions for the electric field equal each other at r = R. Get solution

69. A very long cylindrical rod of nonconducting material with a 3.00-cm radius is given a uniformly distributed positive charge of 6.00 nC per centimeter of its length. Then a cylindrical cavity is drilled all the way through the rod, of radius 1 cm, with its axis located 1.50 cm from the axis of the rod. That is, if, at some cross section of the rod, x- and y-axes are placed so that the center of the rod is at (x,y) = (0,0); then the center of the cylindrical cavity is at (x,y) = (0,1.50). The creation of the cavity does not disturb the charge on the remainder of the rod that has not been drilled away; it just removes the charge from the region in the cavity. Find the electric field at the point (x,y) = (2.00,1.00). Get solution

70. What is the electric field at a point P, which is at a distance h = 20.0 cm above an infinite sheet of charge that has a charge distribution of 1.30 C/m2 and a hole of radius 5.00 cm whose center is directly below P, as shown in the figure? Plot the electric field as a function of h in terms of σ/(2ε0).... Get solution

71. A cube has an edge length of 1.00 m. An electric field acting on the cube from outside has a constant magnitude of 150 N/C and its direction is also constant but unspecified (not necessarily along any edges of the cube). What is the total charge within the cube? Get solution

72. A carbon monoxide (CO) molecule has a dipole moment of approximately 8.0·10–30 C m. If the carbon and oxygen atoms are separated by 1.2·10–10 m, find the net charge on each atom and the maximum amount of torque the molecule would experience in an electric field of 500.0 N/C. Get solution

73. An infinitely long, solid cylinder of radius R = 9.00 cm, with a uniform charge per unit of volume of ρ = 6.40·10–8 C/m3, is centered about the y-axis. Find the magnitude of the electric field at a radius r = 4.00 cm from the center of this cylinder. Get solution

74. Find the magnitudes and the directions of the electric fields needed to counteract the weight of (a) an electron and (b) a proton at the Earth’s surface. Get solution

75. A solid metal sphere of radius 8.00 cm, with a total charge of 10.0 µC, is surrounded by a metallic shell with a radius of 15.0 cm carrying a –5.00-µC charge. The sphere and the shell are both inside a larger metallic shell of inner radius 20.0 cm and outer radius 24.0 cm. The sphere and the two shells are concentric.a) What is the charge on the inner wall of the larger shell?b) If the electric field outside the larger shell is zero, what is the charge on the outer wall of the shell? Get solution

77. There is an electric field of magnitude 150. N/C, directed vertically downward, near the surface of the Earth. Find the acceleration (magnitude and direction) of an electron released near the Earth’s surface. Get solution

79. A 30.0-cm-long uniformly charged rod is sealed in a container. The total electric flux leaving the container is 1.46·106 N m2/C. Determine the linear charge distribution on the rod. Get solution

80. A long conducting wire with charge distribution λ and radius r produces an electric field of 2.73 N/C just outside its surface. What is the magnitude of the electric field just outside the surface of another wire with charge distribution 0.810 λ and radius 6.50r? Get solution

81. An object with mass m = 1.00 g and charge q is placed at point A, which is 0.0500 m above an infinitely large, uniformly charged, nonconducting sheet (σ = –3.50 · 10–5 C/m2), as shown in the figure. Gravity is acting downward (g = 9.81 m/s2). Determine the number, N, of electrons that must be added to or removed from the object for the object to remain motionless above the charged plane.... Get solution

82. A proton enters the gap between a pair of metal plates (an electrostatic separator) that produce a uniform, vertical electric field between them. Ignore the effect of gravity on the proton.a) Assuming that the length of the plates is 15.0 cm and that the proton approaches the plates with a speed of 15.0 km/s, what electric field strength should the plates be designed to provide so that the proton will be deflected vertically by 1.50·10–3 rad?b) What speed will the proton have after exiting the electric field?c) Suppose the proton is one in a beam of protons that has been contaminated with positively charged kaons, particles whose mass is 494 MeV/c2 (8.81·10–28 kg), while the mass of the proton is 938 MeV/c2 (1.67·10–27 kg). The kaons have a charge of +1e, just like the protons. If the electrostatic separator is designed to give the protons a deflection of 1.20·10–3 rad, what deflection will kaons with the same momentum as the protons experience? Get solution

83. Consider a uniform nonconducting sphere with a surface charge density ρ = 3.57·10–6 C/m3 and a radius R = 1.72 m. What is the magnitude of the electric field 0.530 m from the center of the sphere? Get solution

84. A uniform sphere has a radius R and a total charge +Q, uniformly distributed throughout its volume. It is surrounded by a thick spherical shell carrying a total charge –Q, also uniformly distributed, and having an outer radius of 2R. What is the electric field as a function of R? Get solution

85. If a charge is held in place above a large, flat, grounded, conducting slab, such as a floor, it will experience a downward force toward the floor. In fact, the electric field in the room above the floor will be exactly the same as that produced by the original charge plus a “mirror image” charge, equal in magnitude and opposite in sign, as far below the floor as the original charge is above it. Of course, there is no charge below the floor; the effect is produced by the surface charge distribution induced on the floor by the original charge.a) Describe or sketch the electric field lines in the room above the floor.b) If the original charge is 1.00 μC at a distance of 50.0 cm above the floor, calculate the downward force on this charge.c) Find the electric field at (just above) the floor, as a function of the horizontal distance from the point on the floor directly under the original charge. Assume that the original charge is a point charge, +q, at a distance a above the floor. Ignore any effects of walls or ceiling.d) Find the surface charge distribution σ (ρ) induced on the floor.e) Calculate the total surface charge induced on the floor. Get solution

86. A long, horizontal, conducting wire has the charge density λ = 2.849·10–12 C/m. A proton (mass = 1.673·10–27 kg) is placed 0.6815 m above the wire and released. What is the magnitude of the initial acceleration of the proton? Get solution

87. A long, horizontal, conducting wire has the charge density λ. A proton (mass = 1.673·10–27 kg) is placed 0.6897 m above the wire and released. The magnitude of the initial acceleration of the proton is 1.111·107 m/s2. What is the charge density on the wire? Get solution

88. A long, horizontal, conducting wire has the charge density λ = 6.055·10–12 C/m. A proton (mass = 1.673·10–27 kg) is placed a distance d above the wire and released. The magnitude of the initial acceleration of the proton is 1.494·107 m/s2. What is the distance d? Get solution

89. There is a uniform charge distribution of λ = 5.635·10–8 C/m along a thin wire of length L = 22.13 cm. The wire is then curved into a semicircle that is centered at the origin and has a radius of R = L/π. Find the magnitude of the electric field at the center of the semicircle. Get solution

90. There is a uniform charge distribution λ along a thin wire of length L = 10.55 cm. The wire is then curved into a semicircle that is centered at the origin and has a radius of R = L/π. The magnitude of the electric field at the center of the semicircle is 3.117·104 N/C. What is the value of λ? Get solution

91. There is a uniform charge distribution of λ = 6.005·10–8 C/m along a thin wire of length L. The wire is then curved into a semicircle that is centered at the origin and has a radius of R = L/π. The magnitude of the electric field at the center of the semicircle is 2.425·104 N/C. What is the value of L? Get solution


Chapter #40 Solutions - University Physics with Modern Physics Volume 2 (Chapters 21-40) - Gary Westfall, Wolfgang Bauer - 2nd Edition

1cc. Which isotope X is needed to complete the reaction ...a) ...b) ...c) ...d) ...e) ... Get solution 1mcq. Radium-226 decays by e...