94.20: A magnet is dropped through a verti:fe t /w5fr9gbcal copper pipe slightly larger than the magnet. Relative to the speed rfw t/f9b eg5:it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the dimob r an2)t:k)rection of an induced current in a conductor by t)nm)bo :2r aka magnetic field could be a restatement of

  11.25: The product (5+nyu)qs . xw6p0tqnm/ ke,kw 3 Teslas) × (2 meters) × (4 meters/second) is equivalent to which onenquw, mkq6/y) pt +wxs. 0ne5k of the following?

  04.34: A square loop is placed in a uniform magnetic f wnybj ;sip8o8/m+g*f ield perpendicular to the plane of the loop bgoj 8+i f8;yspwn /*mas 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 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 the page. z+b(ga+6x foi The wire experiences an induced charge separation as shown. Whzxi(6a b+gf+oich way is the wire moving?

  00.20: A wire moves witso,lz;;gp p( 6ub yuru, +6nzin:t2jth a velocity v through a magnetic field and experiences an induced ( nuztz; +upyr :jt u n6o2g6,b,psl;icharge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows (gauoi. (4e qla 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 in the area contained within the conducting raiagu e(q(.o4li ls?

  00.10: When a wire moving through a magnetic / -f:+xcrco bypjr02 afield has a voltage induced between the wire’ -2rpb fa yo/c:j0crx+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 jz*/61a)-wvvuqr.v4hrvg g ahas constant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnezv w*1)vvh6a./ v qjrgu4-rgatic field are all mutually perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-o8 gkeuut .tv6ti tn.:8n 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, decreases uniformly in time at the same rate for each circuit. Rank the circuits forg6i88.etk. uvt:tn ut the brightness of the bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (wt.1mtdpo ,cx .d;cvu/ hich 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 inxm;o .d ctv,c d.u1t/p the right-hand circuit move in response to this change?

  08.29: A strong bar magnet is held very rol64 ix an.:k4qt4jrclose to the opening of a solenoid as shown in the diagram. As the magnelrnx k jr44q46.oat :it 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 induced current?

  09.37: For the figure shown, the vari.a6sx /hyc4o gable resistance 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 ao6ac.4hgxs y/nd 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 opening of a solenoid av)60o /mikd fv4b(a xjs 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 current in the solk)id6 xv /jo4v fm(0abenoid and which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loop7go88xjwvs*8lv (zowi bq6zt6.yf+ u s 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 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 fi zous.88vw66x7b8t+jfz y wolv *g(iqgure from above)?

  11.41: For the figure shown, the variable rph*jg )dt7.kut 3 m;xoesistance 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 innerci*toa: q( nhgi*rcuit $R_{inner}$ 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 zebnp468 jmb1 c (5xhtwire loop sits in a plane perpendicular to a spatially uniform magnetic field poib4t51bh 8jncx6 mp(e znting 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 to5d m9 nwh4fn,x fkv,.t a wire with conventional current directed up the page. A scientist then moves the loops away from the current as shown. What is the orientation of the conventional current in each loop whi,hwff 9,x5vk .dnnmt4le this occurs?

  17.35: A metal bar is moving to the ltvu )hm(heeh/zjy4 ;6eft 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 choi/;4uz6j vetyh m)(hehces correctly indicates 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 solenqz;e9s1st6s)x f nk5noid passes through the circuit as shown. The magnetic field of the solenoid, direct5fkz 9sssqnnx; et1) 6ed 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 th2bktij.h6 , hau09 kxnds1n;ne 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 buld1k ah6nh; ,nnb ksutx02 i.j9bs 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?