94.20: A magnet is dropped through a vertical copper pipe slightly lmzkj:ijm ui+34ej 64hc5dmz8b 4k6wb arger than the magnet. Relative to the speed it would fall in air, the magnet in the pip8w 6 4k4jh juk5 zi:bjzeb3md+cmi46me falls:

  01.30: Lenz's law concerning the direction of an induced currenttn/ .xz 5cjcmg: p6y4m in a conductor by a magnetic fm: t5 n/zcg4 cjpm6.yxield could be a restatement of

  11.25: The product (3 Teslas) × (2kh 2+9qet he22r of 4pdp(1kst meters) × (4 meters/second) is equivalent to which one of the foll re9+tfpph2sdkh k1 2t(o2q 4eowing?

  04.34: A square loop is placed in a uniform magnetic field perpendiculal xc6uk )wz;vabt 9uc3x) r5h,r 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. If the loop is rotated through an angle of x6uu,hx lk59av;)3wc) t rcbz $90^{\circ}$ in 0.1 second what would be the average (RMS) induced EMF in the loop?

  97.32: A wire moves theb rc*x v)e nr/v7:0kudj/ (hhrough a magnetic field directed into the page. The wire experiences an kh)brj/r:nuvh(*0 c7e/xdve induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field an os) rks8u 0;/vmz3:3lwafzxs l p3o1vd experiences an induced charg30 xss/ ufl)3v 3mrokaow lz8zp; v1:se separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on two conducting rails.s2a w prh*yf2*9c frj. To make an induced current i in the direction indicated, in what direction would the magnetic field be in the area contained a.s9*yf 2*crh p2rfwj within the conducting rails?

  00.10: When a wire moving throughwl 7 )vjr/nnuo2fk(4 ( fptf(y a magnetic field has a voltage induced between the wire’s ends, that voltage 4ju/( 7 p)wffn 2yfntr(vk (lois
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 ha:qxne- .t+p3 jh+f aq8dx11x bgf8s dks constant velocity 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 potential difference induced across the rod’s length?d+.t 8b s8 3d-n: gaqfe1phxf+xq1jxk

  04.42: A solenoid is oriented end-on so that*j frybz3 i.crm,v2 +h 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 resistance is added as shown. Assume that the magnetic field from the sole yfvm*jrhbz3.+,r2cinoid, 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 (whichls:+2qbbyy1g 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 re1lb+ yy:g bs2qsponse to this change?

  08.29: A strong bar magnet is he.o*hw, lmq14ldz:q a jld very close to the opening of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid at constant speed,lq:w.,1 4dqoamzj lh* 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 figur6fho z; e)*qj 8mri;mpe shown, the variable resistance 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 the center of the left-hand circuit and in what direction is the convenzif jr);*6oe8 hpmq;m tional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is held very c75- mmwnef e-nlk rr hm-8m4.ilose 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 thm-8kn -4-efl rmie57w.mn rhm e force on the bar magnet because of the induced current in the solenoid and which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of resistive w,lc+vxtrp lt)(z g41 cire are placed next to each other as in the figure. The circular loop on the left isctt1z(l,p)g 4+lvc r x 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 resistance of the oudk mk*8 -znl)avvv,;tter 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 resiew l*m0podv1 l+n0kk2stance 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.vokl0q(f5pvkct /y(b q sl91 sits in a plane perpendicular to a spatially uniform 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 f 1q c ytv.(kb(p5so9vqlk0/ lbest describes the result of this field increase?

  16.47: Two small loops of wire are located close to a wire with cvxc61l-98nzv :yz72oo(7qa n ietb gu onventional current directed up the page. A scientist then moves the loops away from the current as shown. What is the orienz( 7nc -ob8 v7tlev196 :gxa y2qnuozitation of the conventional current in each loop while this occurs?

  17.35: A metal bar is moving to the left across a set of fricti/ iakoxo xv.vjr09-0lonless conducting rails as seen in the figure. Throughout 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 vl9k- 00. xxvr /aojoibetween the magnitude of the currents through each resistor at the instant shown?

  08.50:. An infinitely long , lz uzld.z5.fsolenoid passes through the circuit as shown. The magnetic field of the sofzzl,.5d l.zulenoid, 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 dibt im+l z40u+ cr5ucz-rected into the plane of the page is decreasing in time. A +ruiult5- 4 c+0cbzmzconstant emf ξ 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?