ASSIGNMENT #12

DUE ON DECEMBER 1, 2005

HAND-IN

CHAPTER #29:

QUESTIONS:

7   Figure 29-30 shows four circular Amperian loops (a, b, c, d) concentric with a wire whose current is directed out of the page. The current is uniform across the wire's circular cross section (the shaded region). Rank the loops according to the magnitude of around each, greatest first.

PROBLEMS:

•••23 Figure 29-51 shows a cross section of a long thin ribbon of width w = 4.91 cm that is carrying a uniformly distributed total current into the page. In unit-vector notation, what is the magnetic field at a point P in the plane of the ribbon at a distance d = 2.16 cm from its edge? (Hint: Imagine the ribbon as being constructed from many long, thin, parallel wires.)

•••25 In Figure 29-53, length a is 4.7 cm and current i is 13 A. What are the (a) magnitude and (b) direction (into or out of the page) of the magnetic field at point P? (Note that these are not long sections of wire.)

•••33 In Figure 29-58, a long straight wire carries a current i₁ = 30.0 A and a rectangular loop carries current i₂ = 20.0 A. Take a = 1.00 cm, b = 8.00 cm, and L = 30.0 cm. In unit-vector notation, what is the net force on the loop due to i₁?

61 Figure 29-75 shows a cross section of a long cylindrical conductor of radius a = 4.00 cm containing a long cylindrical hole of radius b = 1.50 cm. The central axes of the cylinder and hole are parallel and are distance d = 2.00 cm apart; current i = 5.25 A is uniformly distributed over the tinted area. (a) What is the magnitude of the magnetic field at the center of the hole? (b) Discuss the two special cases b = 0 and d = 0. (c) Use Ampere's law to show that the magnetic field in the hole is uniform.

CHAPTER #31:

QUESTIONS:

PROBLEMS:

••44 Figure 31-29 shows a driven RLC circuit that contains two identical capacitors and two switches. The emf amplitude is set at 12.0 V, and the driving frequency is set at 60.0 Hz. With both switches open, the current leads the emf by 30.9°. With switch S₁ closed and switch S₂ still open, the emf leads the current by 15.0°. With both switches closed, the current amplitude is 447 mA. What are (a) R, (b) C, and (c) L?

ONLINE

CHAPTER #29:

QUESTIONS:

PROBLEMS:

••38 In Figure 29-63, a long circular pipe with outside radius R = 2.6 cm carries a (uniformly distributed) current i = 8.00 mA into the page. A wire runs parallel to the pipe at a distance of 3.00R from center to center. Find the (a) magnitude and (b) direction (into or out of the page) of the current in the wire such that the net magnetic field at point P has the same magnitude as the net magnetic field at the center of the pipe but is in the opposite direction.

••44 A long solenoid has 100 turns/cm and carries current I. An electron moves within the solenoid in a circle of radius 2.30 cm perpendicular to the solenoid axis. The speed of the electron is 0.0460c (c = speed of light). Find the current I in the solenoid.

CHAPTER #31:

QUESTIONS:

PROBLEMS:

•53 An air conditioner connected to a 120 V rms ac line is equivalent to a 12.0 resistance and a 1.30 inductive reactance in series. Calculate (a) the impedance of the air conditioner and (b) the average rate at which energy is supplied to the appliance.

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