94.20: A magnet is dropped sxe-g xs8t/k+ through a vertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magnet in the pixst8 s +xkg-e/pe falls:

  01.30: Lenz's law concerning the direction 8z:q0x1 *n p+y*onv hzon6qil of an induced current in a conductor by a + l1z h*8x qi*0onqp:no 6nvzymagnetic field could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is ez3(k -8wz )x3cqahn8jz d +xoaquivalent to which one of tzchkn-a za( qx83ow38 x)zdj+ he following?

  04.34: A square loop is placed in a uniform magnetic field perpendicular uzp./n+ f yvh8dkys-6 to the plane of the loop as shown. The loop is 0.5 meters on a side and the magnetic field B has a strength of 2 T. 8vuypykz+/- h.d6s fnIf the loop is rotated through an angle of $90^{\circ}$ in 0.1 second what would be the average (RMS) induced EMF in the loop?

  97.32: A wire moves through a magnetic field dire jo4rbt +: f5do9s1qa v// dodsb0fls;cted into the page. The wire experiences an induced charge separatss9o: o fj+;d1tq 0v/sdl/adb5 fr4 boion as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v tohfm z1 tm9e0js5txr t6 (wt59hrough a magnetic field and experiences an induced charge separation as shown. What is the direction of the magnet56tzs wf9h10o(5met9t m xj rtic field?

  05.33: The figure below sh50 fhhmhc9)yo-u*t x xows a bar moving to the right on two conducting rails. To m-hmthu o*cfxx95 y 0)hake an induced current i in the direction indicated, in what direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field has a vowz9vcoj aq6)1abv3 p9 wu9dxbe74,om ltage induced between the wire’s ends, thatodv)99aqcpow3a6ujmbez, v 914b7 wx voltage is
I. directly proportional to the strength of the magnetic field
II. directly proportional to the velocity of the wire
III. directly proportional to the diameter of the wire

  95.30: A 0.20 m long copper rod has constant velocity 0.30 m/s traveling tg pg*v s),1pshhrough a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potential difference indusps*)gp1 vhg,ced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its open 0u6ijzcjwta9k 9n/n7.1p sce4j8rsoing is perpendicular to the circuit containing the two light bulbs as drawn in figure C1. For figures C2 and C3, a shorting wire of negligible resistance is added as shown. Assume that the j61ekwnrj9cj9 ut/p sz74n s8o0ac i .magnetic field from the solenoid, shown coming out of the plane of the page, decreases uniformly in time at the same rate for each circuit. Rank the circuits for the brightness of the bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (which arerq,7fo 5rm+lw6q af5b assumed to be close to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galvanomwmo+ bqf5q7 ,lr6rf a5eter needle in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet is held very close to the opening of a solenoid g6m2) , i*b*irleirbias shown in the diagram. As the magnet is moved away from the solenoid at constant speed, what is the direction of conventional current through the resistor shown and what is the direction of the force on the magnet )l*i2re i,i m6big*rbbecause of the induced current?

  09.37: For the figure shown, the variable resistance in *y wjh+(sdyl46pspl-s*s) qn the circuit on the left is increased at a constant rate. What is the direction of the magnetic field at the point P at the center of the left-hand circuit and in what direction is the conventional current through the resistor in the right-hanyp n)hl*4qy s psslj6*-w+(ds d circuit?

  10.39: A strong bar magnet is held very close to the opening of ax*opjk2:r pu+ solenoid as shown in the diagram. As the magnet is moved to the left toward the solenoid, a conventional current through the resistor shown is directed from A to B. What is the direction of the force on the bar magnet because of the induced current in the solenoid and which magnetic pole does the “??” in the diagramo2k *jp+:pr xu represent?

  14.34: Two circular loops of resistive wire are placed next to each p3ng2ccu d6 f9other as in the figure. The circular loop on the left is connected to a constant voltage source V. The resistance of this loop is increasing linearly with time. As the resistance is changing, what is the direction of the magnetic field at point P (the center of the left-hand loop) and what is the orientation of the conventional current in the right-hand loop (as viewed in the figure from above)6n93pcg du f2c?

  11.41: For the figure sxw4pnl3t)v,-mer+ e d hown, the variable resistance of the outer circuit $R_{inner}$ is decreasing at a constant rate. While this is occurring, in which direction is the magnetic field associated with the outer circuit at the point P in the plane of the circuit and in which direction is the conventional current through the resistor $R_{outer}$ in the smaller interior circuit? The two circuits lie on a flat table.

  13.35: For the figure shown, the variable resistad7 xy;wpvu,cb lm,-. snce of the innercircuit $R_{inner}$ is increasing at a constant rate. While this isoccurring, in which direction is the magnetic field associated with the inner circuit at the point P in the plane of the circuitand in which direction is the flow of electrons through the resistor labeled $R_{outer}$?

  12.38: A square, conducting wiry2zb a0xq5x,p+k7kj d e loop sits in a plane perpendicular to a spatially uniform magkzx 5 dxb7+0qpka,2y jnetic field pointing into the plane of the page as shown. The magnetic field strength steadily increases with time. Which one of the following effects best describes the result of this field increase?

  16.47: Two small loops of wire are located close to a wr,;d*8+p earo/s, os()sa3gtxuta qd ire with conventional current directed up the page. A scientist then moves the loops awqg*);sed 8+saa/ xdr ,(,att o3usorp ay from the current as shown. What is the orientation of the conventional current in each loop while this occurs?

  17.35: A metal bar is moving to the left across3n, zn ,j8den a ;ipfq25(yvls a set of frictionless conducting rails as seen in the figure. Throughout the region between the rails, tln;8,3 se v5 ,ynanjifz dp(q2here is a uniform magnetic field directed into the plane of the page. The resistors labeled X and Y are identical. Which one of the following choices correctly indicates the direction of the conventional current in the resistors and the relation between the magnitude of the currents through each resistor at the instant shown?

  08.50:. An infinitely long eg b+)fizb f)x +n+s5wwsxe 1+solenoid passes through the circuit as shown. The magnetic field of the solenoid, dwexs exifsb)b5+fz ++)n1g+w irected into the
plane of the page, is weakening which produces a constant emf of magnitude ξ for a closed loop around the outside of the solenoid. Once equilibrium is established in this circuit, what is the voltage across the switch S?

  15.50 A magnetic field directed into the plane of the page is decreasingfz 3 coknd7 )nf257jnt in time. A constant emf j3do2k75fcnn ) ftzn 7ξ is produced for the square loop enclosing the field in the figure. The square loop has three identical light bulbs of resistance R in it and an ideal voltmeter connected to the corners through the center of the loop. What is the magnitude of the voltmeter’s reading?