94.20: A magnet is dropped through at. r+3src e +i36ehwtc vertical copper pipe slightly larger than the magnet. Relative to the speed it would falwct .trer6i3 cse+3h+ l in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an indu+zge(wud rcf- a4rsrko.y6;8 ced current in a conductor by a magnetic field could be a restatemersceg4o.yr( kw 8 urf+- a6dz;nt of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is equivalent tllxev; q u+ t3d+/7owgo which one of wu/v+q dtgl3x+ o;e7l the following?

  04.34: A square loop is placed in a a,hpee);bezxse*axe76fn7dq 1./ h a uniform magnetic field perpendicular to the plane of the loop as shown. The loop is 0.5 meters on a side and the magnetixee,d *)e7a1 ha 6s7.f axqhe;pb/ne zc 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 magnet3 wiq/ :lfbg;,o.e 8abwegqr*d5mek0ic field directed into the page. The wire experiences an induced cw3wil8* gdakme 0efeb :,g bq o.q;/r5harge separation as shown. Which way is the wire moving?

  00.20: A wire moves with lg.ov 4pz-j *ja velocity v through a magnetic field and experiences an inj .lvj4gop- z*duced charge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving -d7p dydil q cn15(o6yto the right on two conducting rails. To make an5-lpony6d i17yddcq( induced current 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 movi(p(-2qcc8mrgq 7j md yst7x9qng through a magnetic field has a voltage induced between the wire’s ends, that voltage qy8t2jm7q(c9g c ds rm(7-qpx 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/s te.nsm ywm,p51nj9k1z8fk t2e9cl x- xraveling through a uniform magnetic fie9cfzjne,nm 8lsmt95 kpw 2-e.1yx1xk ld 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 opening iuj;b.zkp br .c+*n( ges 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 tc.b ;*.ejr( +kuzn bpghe 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 dia +q 90 820ghgiyqyiccopec: :ygram (which are assumed to be close to each otheryqco y9h qi0g2 y:c :08gcpi+e), 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 c/lm zbu 0so dd/(p(z2swwfy6m8ck42 y lose 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 and what is the direction of the force on the magnet becausem8 4 0fy us/pw(mydc2(6/ kwozb zlsd2 of the induced current?

  09.37: For the figure shown, the variable rz 7ayn10lk .vu;phv- xesistance in the circuit on the left is increased at a cons ylzpk;.h -nax1v0v7utant 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 resistor in the right-hand circuit?

  10.39: A strong bar magnet is held very close to the openino9y;g vea-a4sg of a solenoid as shown in the diagram. As the magnet is moved to the ls9 v -oga4aye;eft 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 represent?

  14.34: Two circular loops of resistive wire are placed next to eakokslce2a7,hc1kkdf4*-4zc3 z.h mn ch other as in the figure. The circular loop on the left is connected to a constant voesk-h1.zac 32kokmcf 47k cz*hndl4 ,ltage 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 outer circuit rq q/cue:jk/-5 w.lam$R_{inner}$ 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 resistakq :etlih3(nga4 x7e1 nce 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 perpenf l7 ba4(+f :yyod-7syspu2pj dicular 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 follos2ld a:4 fp(s7y-y+7 jfpu yobwing effects best describes the result of this field increase?

  16.47: Two small loops of wire are located close to a wire with conventional cukw bklk8u.tm5ui*./ y5 lcp2crrent directed up the page. A scientist then moves the loops away from the current as shown. What is the orientation of the conventional cuyktl5km. 8ucb2lw ik5/.u c*prrent in each loop while this occurs?

  17.35: A metal bar is moving to the left acrv3* ks *swdk2voss a set 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 c d vkkw*32vss*urrent 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 through the bc+7c lsup kd h. 3cs 1*/g.;eaoz7drdcircuit as shown. The magnetic field of the shs; dcc.l z.p1ek/gsud*b7ad3 o7+cr olenoid, 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 intoc6st(- og-fqkg* wa)a9xq*p k the plane of 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 resistance R ink p o*(gwfcxt)k*aqg9as--6 q it and an ideal voltmeter connected to the corners through the center of the loop. What is the magnitude of the voltmeter’s reading?