94.20: A magnet is dropped through a vertical copper pipe slightly larger than t u2mmx(vb)6rbim/i5n he magnet. Relative to the speed it would fall in air, thub26 rimmb5v n(m/i x)e magnet in the pipe falls:

  01.30: Lenz's law concerning the direction ofr+jwavu;bo .2 an induced current in a conductor by a magnetic field coua ;+rbuvj.wo2ld be a restatement of

  11.25: The product (3 T-se6j h +lgu np42x(pleslas) × (2 meters) × (4 meters/second) is equivalent to which one of (+p6 s-egpl4 juxhn2lthe following?

  04.34: A square loop is placed in a uniform m k*(*-gjhswobsum w*. re9s3vagnetic field perpendicular 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. bm . ou v3*rsw-(ks9jwsh**geIf 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 into tq78iku k we,97oa(tjzhe page. The wire experiences an induced charge separation9qj7az,euwkkt8 ( oi 7 as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and experi6dt 6b8fw2rb;0tna dnences an induced charge separation as shown. What ibtdda2b680 n6wt rnf; s the direction of the magnetic field?

  05.33: The figure below shows a b*b- 6q joecfdpinzoej--15* ear moving 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 oeo-z bcnf5ei-*-6j j pe1 q*dthe area contained within the conducting rails?

  00.10: When a wire moving through a magnetic fi:lt9aqi prvw5 69x. cc llog*:eld has a voltage induced between the wire’s ends, that voltage is cp w9v ax.gti*cl :5l:9o6lrq
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 travet/puw4v x p2q,1 :eysfling through 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 r:1v2q/ tp,epuywxf4sod’s length?

  04.42: A solenoid is oriented end-on pxb5as/dg - z-w mkx)o6t(j b;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, decrea jx;kw-z6og/xbs-)t5b(mp ad ses 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 ar4 jn6u(c+lqudpwc j *t xr7syt1e;s/8e assumed to be close to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galv8e6l c; 4pw*j1uq/ j yct dn(u7rtssx+anometer needle in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet is gbh/emw*x; x3 held very close 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 gh/*w xxm;be3of the force on the magnet because of the induced current?

  09.37: For the figure shown, the variable resistance in the circuit w4sv4 0znda-9 :d f+s4dwweakon 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 resistor in the right-han 9zfs4wd+4ea:k -w sv4a wd0dnd circuit?

  10.39: A strong bar magnevz4vz a6h;12g0ii9 kewdfp 5r4 gpv8ct is held very close to the opening of a solenoid as shown in the diagram. As the magnet is moved to the left toward the solenoid, a conr5 czhwv g vzd9ipf6a0ekp 1v;2g844i ventional 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 loopshd 2,xop4u::fb7 ph(sun,wuv 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 v x7,o2,fshhpwbup:(nu 4: duthe 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 thgc)e*k5gnt lrclj)3*e 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,ic o.a5 uh+f9+nt nyu44jph/ p 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 loop sits in a plane a:uo4 ,eho pr)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 ef)4u e:,o phoarfects best describes the result of this field increase?

  16.47: Two small loops of wire are located close to a wire 4 no 1juy+3d zkt i9u9(r0ezv0zmuq.n with conventional current directed up the page. A scientist then moves the loops away from the r3u 9 kom 1u+yt.dz0qez4vnni9j0 (zucurrent as shown. What is the orientation of the conventional current in each loop while this occurs?

  17.35: A metal bar is movip1s.1pbx cf k7ng to the left across 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 indicfkc7x1p. pb1 sates 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 solenoid passes through the circuit as shown. The :c21-pddzi av/g-mtwf +b4hbmagnetic field of tdg- mh/2tb df p:wv1i4bac-z+he 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 iseds65bta2pya k,v3lj*3 4bft decreasing in time. A constant emf ξ is produced for the square loop enclosing the field in the figure. The square loop has three iba e2sk * tp4356b3valjty,fddentical 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?