A student makes a short electromagnet by winding Figure 29-71 48. R R R Wire Pipe P

Chapter 29, Problem 57

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A student makes a short electromagnet by winding Figure 29-71 48. R R R Wire Pipe P Figure 29-72 56. x y P s R i i 2 1 y 0 L (a) (b) 20 0 40 0 ys By ( T) y (cm) Figure 29-74 60. 61 A circular loop of radius 12 cm carries a current of 15 A. A flat coil of radius 0.82 cm, having 50 turns and a current of 1.3 A, is concentric with the loop. The plane of the loop is perpendicular to the plane of the coil. Assume the loops magnetic field is uniform across the coil. What is the magnitude of (a) the magnetic field produced by the loop at its center and (b) the torque on the coil due to the loop? 62 In Fig. 29-75, current i 56.2 mA is set up in a loop having two radial lengths and two semicir300 turns of wire around a wooden cylinder of diameter d 5.0 cm. The coil is connected to a battery producing a current of 4.0 A in the wire. (a) What is the magnitude of the magnetic dipole moment of this device? (b) At what axial distance d will the magnetic field have the magnitude 5.0 mT (approximately one-tenth that of Earths magnetic field)?