94.20: A magnet is dropped through a vertical copper pipe slightly larger:rai5pmv7r6cj: ovhmj4:6 *cw ,w wmv than the magnet. Relative to the speed it would fall in air, the magnet in the piph5ai:4v mv,wwc7jwmm6:6 vcr: ojp*r e falls:

  01.30: Lenz's law concerning thejhkf3 c8f d(;2 bnpje. direction of an induced current in a conductor by phkjb;. (8ffnd j2c e3a magnetic field could be a restatement of

  11.25: The product (3 Teslas) × (2 metersz j67 rufl-:50 ys;(kdt xv6 .dlgumbj) × (4 meters/second) is equivalent to which one ul6:d jlj g .yu tsbz5-06kvf7( xrdm;of the following?

  04.34: A square loop is placed in a uniform magnetic fiec(lmb b:2)r:(dl i /ux ,ovvqhld perpendicular to the plane of the loop as shown. The loop is 0.5 meters on a side and the magnetic f((i)/bql,cldxru:ho: 2bvm v ield 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 +/.fytv bcg*zkyh9+hinto the page. The wire experiences an induced charge separation as shown. Which way is the wire moving++ zy9f.v ck*bgyhth/?

  00.20: A wire moves with3/d 2awy11iig e2noct a velocity v through a magnetic field and experiences an induced charge separation as shown. What is the direction of the magnetic field1dwoegny22 3ict ai1/ ?

  05.33: The figure below shows :c--ybcoi 6i+ y qgq3(y hmti8v4w n1ha bar moving to the right on two conducting rails. To make an induced current i in the direction indicated, in what direction would the magnetic fie 6 ii4-oitq1 cbycn3(gv+ymy h:8w-hqld be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field has a voltage induced bet8 nbthx* (c2ikwasx: juo 56w3ween the ba5 (6jn :ouhx*i k38 wstc2wxwire’s ends, that 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 constant velocity 0.30 m/s tr01 xid3p /(xyqb cyyd:aveling through a uniform magnetic field of 0.060 T. The rod, velocity, and my yx3p b(ydxqid:0/ 1cagnetic 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 f; 6ncfq mc0w*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 tcf qfcnw ;m6*0he 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 mp/lp: 6f*zfv* :qo vvt1z2mq (which are assumed 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 in respon* v fz */:v:vtm2fmpz1o6 pqqlse to this change?

  08.29: A strong bar magnet is held very close to the open .yiu:r *tf5d/hr2 dsjing 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 h yu .r*it:f/2j rdd5sis the direction of the force on the magnet because of the induced current?

  09.37: For the figure shown, the variable resistance in the ci2:a,9piyot10 ztlb. s l9bajxrcuit 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 thrsx 9:, lopya jbalt0. 2zti9b1ough the resistor in the right-hand circuit?

  10.39: A strong bar magnet is held vvdkv((5 gp88mzwd)e s ery 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. Whdmkdpw 885)sg (zv(ev at 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 ar 0 bzq gfxs3;/)h+bokle 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 increas/ fqxg +hbzbo3l0;k) sing 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 resistan;hc:5 ps8qzqc x3fsz0 ce 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 resistanc3k-yk :edqos -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 )ro0tt5 r t/ikloop sits in a plane perpendicular to a spatially unifororti5)kr t/0tm 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 increase?

  16.47: Two small loops of wire are located close to a wire with conventzb/f92ld4zcun zd4(v ional current directed up the page. A scientist then moves the loops away from the current as shown. What is the orien ld2dz(v4c9/bz n4 ufztation of the conventional current in each loop while this occurs?

  17.35: A metal bar is moving to the left across a set of frictionless conductpo-.o e-i aa:ging 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 theeo piga:-a-o. magnitude of the currents through each resistor at the instant shown?

  08.50:. An infinitely long solenoid passes through crj2racw +12 i(wipw1 the circuit as shown. The magnetic field of the solenoid, directed into +www ( ipijcr21rc1 2athe
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 direc q5j jc.m9d7 tb*mhc3(vkp0pdted into 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. .p95c 0jqdcjpt(dv3b*hk7m m 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?