94.20: A magnet is dr)el4 bp f6o8ipopped through a vertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magnet in the pi6) b8 pp4ifoelpe falls:

  01.30: Lenz's law concerning the direction of an induced curre)b,gxcvu 3xethrjh3s 8wn+-f0 2z ) gqnt in a conductor by gg,v cuxhsq)t8 -hz rf 3w32nbj xe)+0a magnetic field could be a restatement of

  11.25: The product (3 Tesla 0( fwa, :2 zqqj5t(nw+zl,d9atyp ahds) × (2 meters) × (4 meters/second) is equivalent to which o0jha(ldwp9+y (f,zaqant2 dz q:,tw5ne of the following?

  04.34: A square loop is placed (fn-( fowihn ;in a uniform magnetic field 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 the loop is rotated through an ann h-;nfoi ((fwgle 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 mag 7487pttsz7je mq o0qgnetic field directed into the page. The wire experiences an indu8e p osqj0g tt47m7z7qced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic fie5/zi dp( :lrveld and experiences an induced charge zrl( :i/epvd5separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to :+4g ua1:ii pmlz(cprthe right on two conducting railsipi4+:1 z : cualmgrp(. 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 rails?

  00.10: When a wire moving through a magnetic field has a voltage induced betweet4xrjxx io4cru fb1 v56z1xz2qo, 2) yn j,26zzo )4b1xufxiro tqy2vrc45xx 1the wire’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 vb6fjm-q b 05:cms9e 5c0sef :elf6bwvelocity 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:e:6 sbmveje0-0s mqb fwf55 b9c6flc’s length?

  04.42: A solenoid is i mn muv.;(v eyng3rb)vq9k/ru.4h4 poriented end-on so that its opening is perpendicular to the circuit containing the two lighu4 rum(nhvmb ..r yqv/3g94)ikvnep; t 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 diagdsr7 qk co5k3se2wo -e(s2 ia-ram (which are assumed to be close to each other), the resistance of the left-hao-a skoi (r -c735se2dwk2q send 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 close to the opening of a solenoi6uq.1rn 5vtmef(1xl(w av01sw+c lx fd 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 resisc1wf 1xwvu(q5(ml 6nsexf1av+.l rt 0tor 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 resiuwh. +4w60x1tg uxy jwstance in the circuit on the left is increased at a constant rate. What is the direction of the magxuy4w+ xw 6.jtu10w ghnetic field 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 very close to the ope85 e7gsp li n2mch9m+xning 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 frommnx8gl2+5cp 9 imseh7 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 resistivr5o e/crdpt.f,2u-np 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 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 currtp2.u5/ ,cfd r-n peorent in the right-hand loop (as viewed in the figure from above)?

  11.41: For the figure shown, the )obn9ih 1 wqg0l r54hmvariable 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 u+) c ay ,bx-y*o2ls9v ndl:hiinnercircuit $R_{inner}$ 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 loopzp 3 n64rm,o2;gmqn ar1iumo0 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 ,i4 oapzuomg 1qrr6 0n3m2n; meffects best describes the result of this field increase?

  16.47: Two small loops of wire are locate8 tq;ldiqun5 s tma*/2r2)ri0pwsxo8d close to a wire with conventional current directed up the page. A slsq8a* ;m2/ndiswpxt582r i0 qtuor) cientist then moves the loops 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 moving to the left across a set of frictionless conducp8f0crl *-bsh ting 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 the magnitude of the currents t*c ps fhrb0l-8hrough each resistor at the instant shown?

  08.50:. An infinitely long solenoid passes through the circuit asdpu6i*l;cukm5)h ha 7 t7 ff7s shown. The magnetic field of the sole * cls7hft ih);u7dumpk765 afnoid, 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 dekkmhd.4 ps2 5 vy9 2m,emma3fecreasing in time. A constant emf ξ is provkmy3, ae5p d2294msmf.he mkduced 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?