94.20: A magnet is dropped through a5*l)tdpjff lde.y/t,y4 *km s vertical copper pipe slightly larger than tm d) *eptyyd*jt,5 llf. kf4s/he magnet. Relative to the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerzwex0 go/qb*y5e2av 9ussd+. 6 .lwbn ning the direction of an induced current in a conductor by a magnetic w/u2s +nz b*59ewog vyx.d sela60.qbfield could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is equivalent td,anj4xuz +dml5 jmt9f9i:3 uo which one of the followi3fzd:um,5u9m jaxd l4t 9i+nj ng?

  04.34: A square loop is placed in a uniform magnetic field perpendie)-zz 1q )bx skv0q)ufcular to the plane of the loop as shown. The loop is 0.5 meters on a side and the magnetic field B hub-zqx)ke )qz1 )0fsvas 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 magnetidxz ;1 4gktyaayk1vj8uzg -1.c field directed into the page. The wire experiences an induced charge separayutga-yk.z8a;gk1v xzd4 j 1 1tion as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and expokf8at *crn 7se 3a:t1epm-l3 eriences an induced charge separation as shown. What is the direction ofert:n3 l e3pf-8a*7oa 1ksmtc the magnetic field?

  05.33: The figure below shows a bar movitmxkr0i,zvkk;ch-w .w c,6(hng 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 con,h kikcv,zx.; wrc(kw-h t0m 6ducting rails?

  00.10: When a wire moving 6 e0a ; o;if53kiiflh- ce:blbthrough a magnetic field has a voltage induced between the wire’s ends, that :3 l i6i0lb ahfi;b-eo5;cekfvoltage 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 0.3/io ctm7sz jnnj**.( n0 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magne njj/ *ino.m*zst(7nc tic 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 is perpendi8xm-d .vcsp x/cular to the c dp.m8vxcx- s/ircuit 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 for the brightness of the bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (which areasao02.qk j7 x assumed to be close to each other), the resistance of the left-hand circuit is slowly inc2j07xo .skaqareased. 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 close to the openiv hq: 6so5zyc k. -+3pndw8begng of a solenoid as shown in the diagram. As the magnet is moved away from the sol hckq.pysd: - z3b5w+vgne o68enoid 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 variable resistance in the c f4 + 1o9nk:gxhmy2pooircuit on the left is increased at a constant rate. What is the direction of the magnetic field at the point P at the ceoh+o xoymn f9 2p1:k4gnter 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 very close to the opeawozb :m:;9s5dj6usm+r(( n1ru wt ib ning 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. 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 “tmsdmsz+bb(5:9w:6ur iw(ua rojn ;1??” in the diagram represent?

  14.34: Two circular loops of resist1lxp 4n8 fpd8y qjj;e4ive 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 tpdp8;l41 j jq eyn48fxhe figure from above)?

  11.41: For the figure shrm uv6( ,t5sa3kd-w6epq2 ixt own, the 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 show8 um y-hqhk7n1n, 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;fot(fcl8pf x m303lin,(n pv 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 thisnfpi (v8 l(;3lffpt 3mx 0,cno field increase?

  16.47: Two small loops of wire are located /1pqzbbk5 ccn.q 88w4f:g tvn close to a wire with conventional current directed up the page. A scientist then moves the loop gn:.4zk/ c qnbqf1ct5vbpw88 s 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 movidqv27 9jc11 a(lkhku g3l(.js ct*nfy ng 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 f9l7(gvs(qc1 d f2huclja k.*tky13 jn ield 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 the magnitude of the currents through each resistor at the instant shown?

  08.50:. An infinitely long solenoid passesclybkom6;x -a 9;c 9:6ekspm b through the circuit as shown. The magnetic field of the solenoid, directed into the m9 m6l;bc6 seb-;ky9a x ok:cp
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 6chmz:p0ah c(directed into the plane of the page is decreasing in time. A constant emf ξ is produced for th(hhm 6pc:a0z ce 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?