94.20: A magnet is dropped through a vertical copper pipe slightckmal-68i jg ;ly larger than the magnet. Relative to the speed it would fall in air, the magnet in the pipmk l8-ia;gj6 ce falls:

  01.30: Lenz's law concerning the direction of an induced current inu, kok;u04x* .7+hqltxig tn m a conductor by a maik uukmlx.7x 0 ;4 t,ohtgnq*+gnetic field could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/seco7yv oi.-u6qpp -kze e3nd) is equivalent to o z eeu.pkqi36-vp-7 ywhich one of the following?

  04.34: A square loop is placed in a uniform magnetic 94qzqo rgf8t ei2we 7.6kliu-field perpendicular to the plane of the loop as shown. The loop isr9 .g6tizeo- lf 24wqiuk8e7q 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 of $90^{\circ}$ in 0.1 second what would be the average (RMS) induced EMF in the loop?

  97.32: A wire moves thronb,-qr rowm j bav-zk148 *zy8ugh a magnetic field directed into the page. The wire experiences an induced charge separation as shown. Which way is the wi no wzk r*r-8- y81qba4mbv,jzre moving?

  00.20: A wire moves with a velocity v through a magnetic fielou ,1zuqjy acl6-qcb , d78i1wd and experiences an induc,y8icj 6db,ow lz7uuq1- a1qced charge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below : p(,vktt8ie)o4ki5q j .pv zmr-5rb wshows a 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 field be krjepo:,t (t i.-mk b5 vq pr5ziv8w)4in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field fndx)yto/j9g,1/g h (u xhto,has a voltage induced between the wire’s ends, t/g1 j n), /fuy9xtt,hhdogxo(hat 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 rogw5dl l;q w-s6 w15wt/ 1g,wvade j1ead has constant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potential difference indulgwt aw6 d w1v; /51sw1-eaelg5qd wj,ced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its opening is pk,)xim)),t m uf 7sb d/oe8afkerpendicular to the circuit containing the two light bulbs as drawn in figure C1. For figures C2 and C3, a shorti ,)k)oex/7b,sm8f ta du i)kfmng 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 asx5k agyv)-yn(sumed to be close to each other), the g( k -5nyxa)vyresistance 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 clo /op1re usm,e4se 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 because of the i s41po/mueer ,nduced current?

  09.37: For the figure shown, the variable resistan /v+ w2 1z9ptdqo xhndg0r.ai/ce in the circuit 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 0 p.1g raondh 2/9/dixvwtq+ zis the conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is held veryx, qyh 2nb,ffdx) +q2n 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 current2,b2+)qnxhq f,x y fnd 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 placedng, re5z:uozgk;m,( k 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 i5gkmz ,k,(ezo ug:n ;rs 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, thwppke * d1;i +5b8l -i1hadavfe 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 variable resistance of the innercirc j ukce7iifu(8.zr 7x7uit $R_{inner}$ 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 perpendicular to a spatiauxg* ; au4r+btlly uniforu gux4t +*b;ram 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 cgb :m3,r-gm fa*os;nblose to a wire with conventional current directed up the page. A scientist then moves the loops b-,na ;*3mfogsr:mgb 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 jja4po t/1 tk/moving 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 indicates the direction of the conventional current in the resistors and thet a/ otkpjj/41 relation between the magnitude of the currents through each resistor at the instant shown?

  08.50:. An infinitely long so8v4l.3a 1 ydibvtrj(gp zca. 4lenoid passes through the circuit as shown. The matvc.v(3 aj.z4b481drig yalpgnetic field of the 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 planfl.jz j am9ak3ek 2p0:e 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 in it and an ideal voltmeter connected to the corners through the center of the loop. What is the magnitude 23pk:a.lm9 eaf z0 jjkof the voltmeter’s reading?