94.20: A magnet is dropped through a-mzm 5;o7wecgj(m p/y vertical copper pipe slightly larger than the magnet. Relative to the speed it weo7 cym /m(-zpmg;5j would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the(h a1(rm350n nnal-zcbri w: q direction of an induced current in a conductor by a magnetic fi 03 :nlzan(abir51m-w hnqc(reld could be a restatement of

  11.25: The product (3 Teslas) × (2 me 8pb+m cmf,u15z/o2i enuq1l1b gqpy8 ters) × (4 meters/second) is equivalent to which one of the q5pbqm 1p+mc/2niuguy b8z8l1e,of1 following?

  04.34: A square loop is placed in a uniform magnetic field pe6 ) 1ki6 tabne t,0o3mfcp6rg:ee)wg mrpendicular 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 pn k6om:3e cb1) ggw amet)0tr6ef,i6an angle of $90^{\circ}$ in 0.1 second what would be the average (RMS) induced EMF in the loop?

  97.32: A wire moves yrfciu2a-3:tthrough a magnetic field directed into the page. The wire exp2iuc3rft-y : aeriences an induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and experienraco1 ;x- 7a cfpd: p(yh:m4yrces an induced charge separation as shown. What is the dir-d o rmf cr1:p;yh7c4apya(: xection of the magnetic field?

  05.33: The figure below shows a bar movind.+ t0 qd1qx.yls,yh tg to the right on two conducting 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 condsq+d0 yqylhx,.d 1.tt ucting rails?

  00.10: When a wire moving through a magnetic field has a voltage induced bet1tdsfdz5h0-qf2lexy d:,; l fween the wire’s ends, that lfs-xqdf dfle t5yd ;zh 2,01: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 constanto*j.io,9 g0zt.p 1j (ydzb/,ab rjoom velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mut bja.y 0(zo p1/od.ozbo ,9jri,gj *mtually perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its opening i;fuv(stxok, /) uwp z +/qxh/rs perpendicular to the circuit containing f+;u qwzp k/o,/(s /)vxruthx 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 labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (which are a/5ym*fylbhwj9,w2g hy8k8*et o ymn+ssumed 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 wey w l8yb8mhgk2, h/* 9ot*my5n+yfj in response to this change?

  08.29: A strong bar magnet is held very close to the opening of a sez;osqw i7 1af m5m2q.h7a:xoolenoid as shown in the diagramm5:7hew qsma7 f qoio. 1za2x;. 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 resistaw1 o5+i 27buqlfl4k frnce in the circuit on the left is increased at a constant rate. What is the direction rbif w+o 5l 2flkqu471of 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 held very close to k2t)6 oj6pkc nwim3u1l/)xsnthe opening of a solenoid as shown in the diagram. As the magnet is moved to the left toward the solenoo ixc6w3l6p/1)k )m nnjst2kuid, 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 wmhp-l6d /8uusire 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 (the center of6up u-lh8 /sdm 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 figurezy0jxas pk* r n-cb24) shown, the variable resistance 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 variable1h9fa4 + bczd vmj9aw. 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 plyr j9;jbnlew.n,zf ; kx15,b/e s3jahane 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 best.wjnel fj1/5s; h n aebryjbzkx,,93 ; describes the result of this field increase?

  16.47: Two small loops of wire are located close to a wi erwii3a f*i:-r;o7lhre with conventional current directed up the7wfr rh:eiii3ol*-a; 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 occurs?

  17.35: A metal bar is moving to the left across a set 8c,2v/h wn-ly:q gqgz 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 qw-l:nqhg , 8 vzgy/c2in the resistors and the relation between the magnitude of the currents through each resistor at the instant shown?

  08.50:. An infinitely long s*ev3 negf5cbwn- c:u3 olenoid passes through the circuit as shown. The magnetic field of the solenoid, directedeb *gnunec5- cw3vf3 : 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 b1epau-bel ) 4tl(c7d of the page is decreasing in time. A constant emf ξ is produced for the square loop (bc)e7a dullb1pet4 -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?