94.20: A magnet is dropped through a vertical copper pipe slightly larger than w4e)-5g jpe tg nq(d;hthe magnet. Relative t jgegw (e)t5pdq4-n ;ho the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concernib- :6 wij xuan/.n6uning the direction of an induced current in a conductor by a magnetic field coj in/6a :iun .uw6nx-buld be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meter;a*kfusf ii 1x6 4bn4-s9lb his/second) is equivalent to which one of the followinif9b4b sku-;* ha nfsx46il1ig?

  04.34: A square loop is placed in a 4a-7qr2 fe :lnnwk 5xquniform magnetic field perpendicular to the plane of the loop as shown. The7n e5:4anx 2k-frw qlq 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 3/u zzs c,23a0pr h 1aank.,aqp+1eprm6ph zninto the page. The wire exp+zrzre zmn63ppa/hs1,a1k3 .a hp0p a nu2c,qeriences an induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a b(ez2k q j7 ;)wdiwq8( lq nt-op1f60vnz2jvy magnetic field and experiences an induced charge separation as shown. What is the direction of the magnqq2k7nbjid)f p-v1z8jq( 6eto0zlwy 2v nw ( ;etic field?

  05.33: The figure below shows a bar moving to the right on two co0*i(eibqb2 ot)iqyc: 0z bk3unducting rails. To make an induced c:qb it0z u qiyki0bo*c3eb)(2urrent 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 volb4 jc0lc aptcv)g-- (ftage induced between the wire’s ends, that vv c(g)cp-j b-taf0lc4oltage 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 hampw8w6j gxbz2o//dheo )jxu;f) 0b z.s constant velocity 0.30 m/s traveling through2wo )8.6 o//uwhezz m)0gjxj; fxb pbd 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?

  04.42: A solenoid is oriented end-on so that its ol mwt:lgwn6kt;x2/83dai4w w pening 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 the bulb labelen /2l ti :w6m;lgtww38aw4dxk d R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (which are assumed to be close tomq gh2 e74p.xyc a)t7h each other), the resistance of the left-hand circuit is slowly increased. In whichm.gt 4pah qxehyc72)7 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 close tohyefe;( b 55z5 hiw)vv 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 and what is the direction of the force on the magnet because of y vhb;z i5w55( hv)efethe induced current?

  09.37: For the figure shown, the variable resistance in thegwwdl :x14p,wdlp 4(g 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 resisto:(x4pw lp4ldd g1,wwg r in the right-hand circuit?

  10.39: A strong bar magnet is held ve ewsn73)ww5zm rp*ft )ry 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 induced current in the solenoid and which magnetic pole does the “??” in the diagram representwf *t zp3s5er7ww))mn?

  14.34: Two circular loops,w e8*h dd l*2*gpzfl --xanbb of resistive wire are placed next to each 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 (the2,zf-gbpb*8e wd -h **l dlanx 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 ouny nsc s58r1t/ter 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 resistanc)o6s6t vr u(vq;jqkt- e 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 plaqbow38* s3beu9 lq*e une perpendicular to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strength steadilyo393qeu*lbuew 8s*b q 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 l j6gwty4pbc 4 mcw;z5 52md9snocated close to a wire with conventional current directed up the pagem4cs2bd5zypwjct 4;5n g 6wm9 . 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 occurs?

  17.35: A metal bar is moving to the left across a s u*fvwd)12nn get of frictionless 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 between the magnitude of the currents throughw2v* ud gf)1nn each resistor at the instant shown?

  08.50:. An infinitely long solenoid passes through the circuit as shown. Ts;.z6ksb 5,du yxn nb nk5ryl55ld h2(he magnetic field2bs 5 ln6hd5z k;(,nrl yxnu5ds.5b yk 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 decreaso; 3:gm eca*0me sgv.m+zi map:0ne9 fing in time. A constant emf ξ is produced for the square loop enclosing the field in the figure. The square lm:aefpe: zoi 09*gae ;vg 3c0msn+. mmoop 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?