94.20: A magnet is dropped through a vertical copper pipe slightly lar )ctueab h*d9fm gt4ii:; )lw(ger than the magnet. Relative to the speed it would fall in air, the magnet in the pi i:) )ic* 9;get(ftald4mhu wbpe falls:

  01.30: Lenz's law concedg9f 5gvf-(lij/x az -;i.bvhrning the direction of an induced current in a conductor by a magnetic fiel5(i;j-a lgf/xgv9d . bhvzi-fd could be a restatement of

  11.25: The product (3 Tesl5 aexkgwlcr w3 ./4xy8as) × (2 meters) × (4 meters/second) is equivalent to which one of the followxyx/8gl ecwkrw54 3.aing?

  04.34: A square loop is placed in a uniform magnetic field perpendicular to thesi) 5y pu;wv5u plane of the loop as shown. The loop is 0.wip u5 5;uvs)y5 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 fiel6 bixc0y 5 m5 (,gseoaf+itnx3d directed into the page. The wire expeiysct6bm f50nx5i, ge 3xao(+riences an induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a vgi rc+7/cav t/elocity v through a magnetic field and experiences an induced charge separa c7tg /raci+/vtion as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right o8nv4 6pu6uyniju1 +by* uuz4n2 bmqy.n two conducting rails. To make an induced curriq u6n *mzb yp y+b u.u6vnjuu2y41n84ent 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 movingqx2 584ozkhsp5,jtrp through a magnetic field has a voltage induced between the wire,jxpr 5o kz428hsqp5t ’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 velo-; vqmmc l(ijm8 .ep+rcity 0.30 m/s traveling through a uniform magnetic field of 0.060 T.;.mvc+(-8mpqlrji me The rod, velocity, and magnetic 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 ur0g -v+7d r;l1p wfigperpendicular to the circuit containing the two light bulbs as drawn in figure C1. For figures C2 and C3, u irpd10r7g;v+w lf- ga 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 a/8 o(aan8.qrr7cx9f a:lme igmz 7.udiagram (which are assumed to be close to each other), the resistance of the left-hand circuit is slowly increased. In which dira. a.rqr fi gmaux8z(o m77:ne9a8 c/lection 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 opening5q ;/f8kgx:fahkhw.fta/ycc 31tt;c of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid at constant speed, what is h;a .a//3hcf5tfct;kckwyfg 81tx q: 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 shomg3dcx n1*zg6 p*i;0w 9kvfe nwn, the variable 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 and in what direction is the con*k c dp9;z13x6gi0vm w*fngenventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is held very close to theigz*tk9 o *ad2 opening of a solenoid as shown in the diagram. As the magnet is moved k*dzat 2*g 9ioto 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 resis)6jqji (/ro3hj j1 gx4qxad5s tive 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)jqh/ rjdg)i 1 jq(xsao3j5x46 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 variable resistance of the outer cirtfdz4ak2-yi8( 2q euvcuit $R_{inner}$ 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 3)m3ojyjc dl+,yhie yp1f30 gresistance 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 perpendicularc;3t- eij p+tf3tbpt2 to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strength steadily increases with time. Whi2t-+3ef3i pjttpct ;bch one of the following effects best describes the result of this field increase?

  16.47: Two small loops of wire are located close to a wnj 8;wui. l.zx/:f ostire with conventional current directed up the page. A scientist then moves the loops azw/.: tl x ju.;s8onifway 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 acrossmjs.4m33 s+ 9eag yy5unt ff:w a set of frictionless conducting rails as seen in the figure. Throughout the region between the rails, there is a uniform magnetic field directedg:j nf.a fm59st 3uy34ymwe+s 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 passes through t7 :)jndp5+39xyrxysaxii k+ a he circuit as shown. The magnetic field of ty+iax3kr5 x )x:asn p9yd+j7i he 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 iscdhq6 w h2d*,tt 8xdo: 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 ligt2t:h8xdd * 6dqocwh ,ht 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?