94.20: A magnet is dropped through ap:-a m x:egg.nm co98t vertical copper pipe slightly larger than the magnet. Relative to the speed it would fal.x : 8n:-e mgto9mpacgl in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the directi5se;t+o0;iwv p dv0 3*dztr ypon of an induced current in a conductor by a magnetic field could be a resrwv t;t*+oip ;de 3p0z5 v0sydtatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 mez 6( lpg0e8hgya;.bf hters/second) is equivalent to whiyhbh gelfz;0pa.(g 68ch one of the following?

  04.34: A square loop is placed in a uniform magnetic field pepc fo1eymy .7p1:zm5cb 4l .gerpendicular 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 g fe.p4.l:m5 b1ypec mzoc71yof $90^{\circ}$ in 0.1 second what would be the average (RMS) induced EMF in the loop?

  97.32: A wire moves through a magneti: kfqfu3 p)ds0c field directed into the page. The wire experiences an induced charge separation as shown. Which way is the wire d:3p0f uq)sfk moving?

  00.20: A wire moves with a velocity v through a *f9p-f/kjjmsl s )7lhmagnetic field and experiences an induced charge se s*sk fl7 -h/)jjflmp9paration as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on i( zri1z:.mpuvw - sa17bx5, drptz (ptwo conducting rails. To make an induced current i in the direction indicated, izm(up r as5, zb- ptidp 7:1i1(rzwx.vn 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 bx(yne cx nea, 4vz*un j3(-7ma voltage induced between the wire’s ends, that voltage is *v, -(ex bxjceu7yz4n3 ann( m
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.x6- ynnwv-ws*ut)k (y30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, andnw-y-st wu(v6* x ky)n 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 sopg8m2*qys 3 5xfv mw 2ria 5ldf9/j7xy 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 o j myfxga3dq7fl2s59w2xpr8 v*m/yi5f the bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (which are as +jkoh sxud4 x:5-arn1hx+.b nsumed to be close to each other), the resistance of the left-hand circuit is slowly increased. I xk1d .rn+uj54+xhh-bxsnao: n which direction does the galvanometer needle in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet is hqgjicyz7l*,a 5-52 7l +oqjvs.r27cg yow o qqeld very close to the opening of a solenoid as shown in the diagram. As the magnet is movecglz y* qj27 r. oqy7wjig+-lq27 5voa c,5osqd 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 va /bv wnc3qzak1;j (xt lhs)b( 1nq0ns9riable resistance in the circuit on the left is increased at a constant rate. What is the direction of t;sk1lzwq3n(s1)a j v0nx (bhqb9n/ tche 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 tx ,nvybe8/j-qvsh j-9 o 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 b xves8 9vh --,jqj/yncurrent in the solenoid and which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of resistive wire are placed next mj 91k7pjb41vxt.qo :mfe u -jto 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 of the left-hand loop) and what is the orientation of the conventional current in the right-hand loop (as viewed m1e f1b7x. oj:-uvjjpk4q9m tin the figure from above)?

  11.41: For the figure shown, the variable resista ,4 m*gy bo7mdu,/qcdpnce 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 variable resgtu2chyq(mb:z, ot we.955 tdy64vvf istance 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 pe c- a)fs s;6n4d q.hs:cbhvfn v)7s yqypj;-7nrpendicular 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 describes the result of this field incres;djs hyv)y4fbq : hnvf7s)p nn.6q- s7cc;-aase?

  16.47: Two small loops of wire are locatevppv9p 7rhe 5; 4w1tabd close to a wire with conventional current directed up the page. A scientist then moves the loops away from the current as shown. What is the orientatr1a5 w p ;vpe49bp7htvion of the conventional current in each loop while this occurs?

  17.35: A metal bar is moving to the left acrzc g5 9u9idg5 8,zbcnnoss 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 curr 58zic u9 z5g,gnc9nbdent in the resistors and the relation between the magnitude of the currents through each resistor at the instant shown?

  08.50:. An infinitely longimz:lj1+c2)fvm1 a p x solenoid passes through the circuit as shown. The magnetic field of the solenoid, direc1zac: v+mxlp j12 i)mfted 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 they n7yn m vh78a mi0t2 -fgf.j3r:inz0r 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 lgi v -20rfyjzn7i n.hm:ar8mt 07yn3fight 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?