94.20: A magnet is dropped through a vertical copper pipe slightly larger than tii l 87jpskws5ffbp52z179cthe magnet. Relative to the speed it b9ti 1pc5w s5z8ik7f fp7 j2slwould fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of )o faz +t7(qw 25qle46piagpoan induced current in a conductor byzio+t4 )(epqf2l qw7aopg6a5 a magnetic field could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) w;ox1 x iuo:r)oc;x7(iowtz/ is equivalent to which one of the follio wi) 7ow urx:1ox(o;t;/xzcowing?

  04.34: A square loop is placed in a uniform/c/sk31 +g-f cmjtnq aefl:g.lez8k- magnetic field perpendicular to the plane of the 8-s/t. cg jme- eafkq kcl1l/g :3znf+loop as shown. The loop is 0.5 meters on a side and the magnetic field B has a strength of 2 T. If 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 directed into th9q xh-zhf 8c3fe page. The wire experiences an induced charge9f8 h3 hz-qcfx separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and exrve as+7p(7o mperiences an induced charge separation as shown. What is the direction of the7+ves r7p(oam magnetic field?

  05.33: The figure below shows a bar moving t4xn3o /1ylur u9 ifc9xnhcb12o the right on two conducting rails. To make an induced current i in the directioc un29y193/ oxrfci14 hnub lxn 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 voltage ir0clx z4x-uhnz n/go)5-mk4 snduced between the ws 4/g - xl n0hom5ucn)zx-r4kzire’s ends, that 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 vvs,u+ yyx 8atlptu:4hi (-)3ix 9rxbu elocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the lu:t isuux )-ay(9t ixyh4,+p xvr8 b3 potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on k(20 eqw,:l ztt-zk yrso that its opening 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 re ztyre:(-2,k ktwqz0l sistance is added as shown. Assume that the 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 . u :0uy;zc b6od)uaxa*jn.0gxtb uc/pv6sa 9shown in the diagram (which are assumed to be close to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galvanometer needle in the right-hand circuit move in response to this cb*/6.tb ; 0:yauxn. u cc9 sjougvz)60xuadpahange?

  08.29: A strong bar magnet is held very close to the opening of a soleiwo1(ofqjn)v h0yeo v /;py*iqys+(a g6e 3) anoid as shown in the diagrafe;w )*i(y syajy3i +1 (6qhvge0panv o)oo/qm. 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 because of the induced current?

  09.37: For the figure shown, the variable resista 4+0vc uye,nctnce in the circuit on the left is increased at a constant rate. What is the direction of the magnetic field at the point P at,c vy0cn 4+eut the center of the left-hand circuit and in what direction is the conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is held very closeth)iknx, e2nbie d./gw -4tw5 to the opening of a 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 mat-iwhn5 kg4w2e. i x etn,bd/)gnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of resistive wire are placed next to each other as ir /d5vs x/g1tsn the figure. The circular loop on the lefts1r v5/xs dg/t 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)?

  11.41: For the figure shown, the variable resistanl6 o0.hvdvh*:1g zdymce 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,j98u8cer:d29v vdtb ixfc12a the variable resistance 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, conductin wxww5/i8d hi1tu4 n0(aj0xkdg wire loop sits in a plane perpendicular to a spatially uniform magnetic f xix (14wjad0u 5h/wwknd8ti 0ield 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 lf w bm*3bj++tkw :myd/f80k2 boah+iwire with conventional current directed up the page. A scientist then moves the loops away from the current as shown. What is the orientation of the conv yalfd+/ 2+ +0bkwmtkf38 jmib*h:bwoentional current in each loop while this occurs?

  17.35: A metal bar is moving to the left across a set of frictionless coi.fyfv cs6f,v jm. t687p)l ;y r(rsdcnducting rails as seen in the figure. Throu . (r,m sfsi8rl;6.)yv6yt fcpcdjv7f ghout the region between the rails, there 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 solenoid passes through the circuitnw.fm4km 1 ..gdwenhfn h4z) 1 as shown. The magnetic em.. . kwmz1nhfwhnd)414 fgn field of the solenoid, directed 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 decreasing ifpggoy6x 0;n(h yah7 +n time. A constant emf ξ is produced for the nya +7(gpyx6 fh0h;gosquare 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?