94.20: A magnet is dropped through a vetkdugb-0 ge )8)1ys sprtical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magnb8gs)1)ek duyt- g0 spet in the pipe falls:

  01.30: Lenz's law concerniu w .ub5usx.z j02jnkjao.l/,ng the direction of an induced current in a conductor by a magnetic field could be a restatement o uls,oj5ukbujn.j /.zwa x.02f

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) fu.sqz6b u:py 4pe 7)cis equivalent to w s:6zpf7c4u.)yuqep bhich one of the following?

  04.34: A square loop is placed t /fs1+picwc4 y7we /i) wvf8nin a uniform magnetic field perpendicular to the plane of the loop as shown. The loop is 0.5 meters on a side a7wfc/ ws 18fv+4ywnetipc ) /ind 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 magnetii;+ha +kwswf*gdl:ko(oj p; 3c field directed into the page. The wire experiences an induced charge separation as shown. Whi 3i;a+*pwk :ojoghwl(f +dsk;ch way is the wire moving?

  00.20: A wire moves with a veload 4i3z, ph(/b *m 1hyjcng95 yhyfgm6city v through a magnetic field and experiences an induced charge separation as shown. What is t4j 6yga,c hp d(3fh hyb5im1m9gyzn */he direction of the magnetic field?

  05.33: The figure below shows a bar moving twnd i4vayb) l. :s/4zfo the right on two conducting rails. To make an induced current i in the direction indicated, in whi lbv/4 4dw.:an)sfz yat direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through8qqd: tflmmnv(e9u j g/9*c+j6wlp 5s a magnetic field has a voltage induced between the wire’s ends, that vl(med*p wvtqc5g sl 9j68j qu+nmf9 :/oltage 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/ ei*5f +en: gb:-,nje-kckp his traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potential difference induced acr*knbpci n:eh k-+ ejg,-fi5e: oss the rod’s length?

  04.42: A solenoid is oriented end-on so that its openinghpxwrp1rsgt. ek * ; 25de46jh 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 magnetic figh21hdr4xrwkt6;.s ejp 5* e peld 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 are assumed to be clhu o,udr-i0 t9ose to each - ro9dut,0hui 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 change?

  08.29: A strong bar magnet is held very.u )dgondyq:* close to the opening of a solenoid as 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)n y*dd gq.o:u and what is the direction of the force on the magnet because of the induced current?

  09.37: For the figure shown, the variable resistance in the circuit on the z u(v4xu5i789me:9c amg bzdk fi d,q*left is increased at a constant rateqb izuac, uedmm598*:d9 kvzx4fi 7(g. 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-hand circuit?

  10.39: A strong bar magnet is xxi,3y x q)p u8)skxb6held very close 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 induceqxy x)xkp6b)3s ix,u8 d current in the solenoid and which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of resistive wire are placed next to each-0zi3, p, isudihg ma. other 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 hi3sd,,aumgiz-.0ip 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 resissvb cmv.f uy6l0,jh99 tance 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 vag;xrs3g -fhq+ riable 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, conducting wire loop sits in a plane perpendicular to a spaj7y dsk 2rkg,2tially uniforsy72d2j,k grk m magnetic 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 closs3t/ :y2ypnch ei (-gse to a wire 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 conventional current in each loop while this occ (p i2s-/3es gynch:yturs?

  17.35: A metal bar is moving to the left acr2 pzc:k,z m/wposs a set of frictionless conducting rails as seen in the figure. Throughp z ,m:2zwk/pcout 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 * s(4r f px1ze+sk7dbh3/xbgjthrough the circuit as shown. The magnetic field of the solenoid, directed into tex(xsk rsh/*3 gp j1zb+d 4b7fhe
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 ow85vf yn* 8sqxf the page is decreasing in time. A constant emf ξ is produced for the square qf8sy 8w* vx5nloop 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?