94.20: A magnet is dropped through a verticalb06 aj.2km,bzazs; al copper pipe slightly larger than the magnet. Relative to the sz2;a,. asla0mb kzj 6bpeed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning t/)r6niu6mj9m nd,qd ya g8 /h2w0 9qr4bafy yxhe direction of an induced current in a conductor by a ma /60mn u ij)gf6 x,d4yd8qb2q9rhymynw /a9ragnetic field could be a restatement of

  11.25: The product (3 Te(b+4 uhly0 8pl-krw mzslas) × (2 meters) × (4 meters/second) is equivalent to which one of the-z0ybrl8 uh+mkl 4pw( following?

  04.34: A square loop is placed in a uniform magnetic field perpendiq.:vyn wf,qd.cular to the plane of the loop as shown. The loop is 0.5 meters on a side and the magnetic fiey.f.,:w nqqvd ld 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 directe25z +wfz o:9dxxriy e;d into the page. The wire experix 5zzfe ixd;w9yr+2o:ences an induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic fiextr+o h5n-/ou qn wfq*q;t0 o3oy(9ctld and experiences an induced charge separationoq ntn/ ouho xq5oytf3 t*c+(q90;rw- as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on two cono+l:jw bg:vm2ducting rails. To make an induced current i in the direction indicated, in what direction would the magnetic field be in the area contained within the conducting ra:bm+lj:g vo w2ils?

  00.10: When a wire moving throu-8lmzkef;-zcx8ip 6 sgh a magnetic field has a voltage induced between teczs mkz 8-if -lp;86xhe wire’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 xgjrrisd,k9 * q ;av;5rq(hii +9fmj:n(ep7 dconstant 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 potpfv 5q;;a*dij ri xm7+ri 9sehd j(n(gkr, :9qential difference induced across the rod’s length?

  04.42: A solenoid is qh)6o*4vfd2bv 2p9g ;q pztgcw3iup3 oriented end-on so 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 resistance 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 th2 wp;ft 4g3giph)vzopdb 32vqu 6 9cq*e bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagramir v349btg hl :h.rpm6 (which are assumed to be close to each other), theimv p hlr9t.4bhr63:g 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 heu66d j y/a;qk2zcuu z+ld very close to the opening of a solenoid as shown in the diagram. As the magnet is moved j6u 6au/;yukz+dqz c2away 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 resistance in the circuit on the left n duix-j 74 *mac7a0emis 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 convejuamndi7 *70a- mx4ec ntional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is held very close to the e1 dy3brh(i y;opening of a solenoid as shown in the diagram. As the magnet is moved to the left towar(e r1y3bhy;idd 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 diagram represent?

  14.34: Two circular loops of resistive wire are placed next to each other asl3r fnrr44ds w)wc 4k* in the figure. The circular loop on the left is connected to a constant voltage source V. The resistance of tc l44k)n3 wd*f4srwrrhis 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 r4n0u r.kindppbil.o/-ac -+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 shownc8q87 gm3dzo.mv nwy0 , 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, conducting wire wsa1p7j7tn es 4-;xrx loop sits in a plane perpendicular to a spatially uniform magnetic ;s7t nx a -xsre74w1pj 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 lopf0o3--9f,6 vsk l3n gqrc8 z wlu;oypcated close to a wire with conventional current directed up the page. A scientist then moves the q,0rpn3 fuwofy;c3l -g sl p9vok8-6zloops away 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 gct kqx2/ -( jymus5xyv0*c4fto the left across a set of frictionless conducting rails as seen in the figure. Throughout the region between the railt yysk* 4xccq-u05 gfvxm /j(2s, 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 soledk,g8a72awj 4w /.jhfyv5dz n0mxx2unoid passes through the circuit as shown. The magnetic field of the sd x0za74u2 2a8wwgf/.x5 n mjhkd,jyvolenoid, 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 2 x/c9y.c )fucur(xtoof the page is decreasing in time. A constant emf ξ is produced for the square loop enclosing the field in the figure. The square loop has three identical light bulbs of resocu 92r(.yfcxt cx /u)istance 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?