94.20: A magnet is droppew a ,j +rhqtmek03efm0sy/8c5d through a vertical copper pipe slightly larger than the magnet. Relative tefct +0mw,8qer sy /mh53 0kajo the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced current in a conduct p3a3 vqja0rq9zt:x6eor by a magnetic field could be a restatemen9vjxa 3 z a0t6qep3r:qt of

  11.25: The product (3 dve 2wnu0+i x3Teslas) × (2 meters) × (4 meters/second) is equivalent to which one of the+x0di 3 vweu2n following?

  04.34: A square loop is placed in a uniform magnetic fieldgg5qc/b /g1,7*j-s k5xzoki uq jced5 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. If thejk j5kc5/ggciqs-/dg o* qe5 17, uxzb 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. The wire a-cffcs 4.qlc wtj0 l:c/ pm+; experiences an induced charge separation as shown. Whicsfpqj-flac 0ct/ m;:cl . +4wch way is the wire moving?

  00.20: A wire moves with a velocitp/4yu l;5v livy v through a magnetic field and experiences an ipli4 v; ulv5y/nduced charge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to t.u3 my, ;ohyulhe 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 c 3;o.hl ,muyuyonducting rails?

  00.10: When a wire moving through a magnetic fao(qvxk qp .a+;aua,7bjj6dytw5e)(ield has a voltage induced between the wire’s ends, that voltao.+ ;dxwaya7bvjk5pe q(ju at q(,a) 6ge 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 un; j7pabcga2qf gc 5,p(-+pc copper rod 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 induced across the rod’5 (;+ggc2uja7fnabpp qp c-c, s length?

  04.42: A solenoid is s8 h*lxtx lt3q3v3(gforiented end-on 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, dt3 3vxtlq *gs3 (f8xhlecreases 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 assumed to be clor- 0)slc(trc(urrmg 1se to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galvanometer n1cmrlu r)tr- c(0( grseedle in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet itc h; 4vgp88cis 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 res4ci;8gcvth p8 istor shown and what is the direction of the force on the magnet because of the induced current?

  09.37: For the figure shown, the variable resistance in the 4is q7 :bt3yf7cw1+ dz zj:rtncircuit on the left is increased at a constant rate. What is the direction of the magnetic fiel74+:ytfb z:rnq zt3 dcjiw s71d 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 vea6c,3c +f limkry close to the opening of a solenoid as shi,k+c63ac m lfown 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 solenoid and which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of resistiv gx:ywe*s0 vu-e 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 chan 0:*ugsx-ywve ging, 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 varcmh6j0hf7f*f+ d h; dwiable 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 variab hld:adb9p) wot;//fxle 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 wiru3dnf ik 8s.:gvt7ebw-pg 54ge loop sits in a plane 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 effects best describes the result of this field increas:e84f7dub gv- s5 .pt 3ggiwnke?

  16.47: Two small loops of wire are located close to a wire with convem c1n5eg )eztxpkr m-pg2:4j-ntional current directed up the page. A scientist then moves the loops away from the current as shown. What is the orn )1 t-k-2ge5 cm4xejgppz:rmientation 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 ci a-5w5bse qd)onducting 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 eiqsd) a5b -5wcurrent 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 aop+lvfgom) (7uebli2 kkne4bu-;)8d* lq u 4ds shown. The magneti2ilp(duo lu )em b ulged+74k)v;-4 *8nqk bfoc 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 plane of the page is decreasing in ) u8am0b s1abp-ed4z6+m y;+qapcpse time. A c6se+;0zam)e pas ub1my8a 4-qdpcp+bonstant 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 of the voltmeter’s reading?