94.20: A magnet is dropped through a vertical copper pipe slightly larger thb fh7o- y(zyhiy h8dn,s4x00man the magnet. Relative t0by h,xo0847 y-fh(imzy nhsdo the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced cur b)r6wo;3yb 3u;ozlvtrent in a conductor by a magnetic field could be a 3bu; zy;wt l obvro63)restatement of

  11.25: The product (3 Teslas) × (2 meters) ×va7a38tbtbx.3 ni4q w (4 meters/second) is equivalent to wh.3viaw nq t4b ba378xtich one of the following?

  04.34: A square loop is placed in a uniform magne3l4e6hr ;qys utic 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 angle ofq43;6 lyrse hu $90^{\circ}$ in 0.1 second what would be the average (RMS) induced EMF in the loop?

  97.32: A wire moves through a dpzpnb++gey8lefy)9 qwv9,4/mh4yh magnetic field directed into the page. The wire experiences an induced chalydy+h,99qeb em+ph /ypv8fn )w4 4z grge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through 62(8 l +wowsu0e jvxxaa magnetic field and experiences an induced charge separation as shown. (ao vx26w 0ejl8w+xusWhat is the direction of the magnetic field?

  05.33: The figure bel5ph t2fk b4nn/tj/q b9lli; /tow shows a bar moving to the right on two conducting rails. To make4j l/f/hibl bt/; qn5ttn9pk2 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 th;5pv t jh79yazrough a magnetic field has a voltage induced between the wire’s; ajyvtp97zh5 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 7) tg*ksd l1 1marr,q)zthy 2lrod has constant velocity 0.30 m/s traveling through a uniform magnetic field ofa q7g tkml1,yrt l hz1r)2ds*) 0.060 T. 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 perpakeu*1udpla e369) x j wh;:yphbz6t3 endicular 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, dtuappy za6d13xu: hh9;wl63 e k* ej)becreases 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 shdq d(*ajl c4etm+du13s zt d:o 7lrwo05y2d-oown in the diagram (which are assumed to be close to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galvanomee2doq t15od*t3dlu maz-wyo4c :(d 7r ljd0s+ ter needle in the right-hand circuit move in response to this change?

  08.29: A strong bar mag .i/ mr,vik9ihnet is 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 resistor shown and what is the direction of the force on the magnet becaiikh,m . r9vi/use of the induced current?

  09.37: For the figure shown, the variable resistance in the circuit on the sjvyvarn/z( mzry+ h 1*42d; pleft is increased at a constant rate. What isy14yvvjmrs zar;pz +*d( 2h n/ the direction of the magnetic 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 tu/g33elo d4 4zyrvas7 he opening of a solenoid as shown in the diagram. As the magnet is moved to the left toward t yoa74/de3zv s 34gulrhe 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 resistive wire are placed next()l(dk:q9 irdbvy5 x pei-sh6 to each other as in the figure. The circular loop on the left is connected to a constan9bv i(yhq: 5) s (x6dklird-pet 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 figure from above)?

  11.41: For the figure shown, the variableo. n7e p.v2x;b+gb3sj8qty:wgkw m a 1 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, the4nf7y *w(uqgw 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, conduczsp+jhy5q 8;)n pl0ak ting wire loop sits in a plane perpendicular to a spatially uniformh+p5n ky)0jp; 8s lqza 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 increase?

  16.47: Two small loops of wire are located close to a wirfu/ tai6, jg*ye with conventional current directed up the page. A scientist thef ,ut*6gyi /jan 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 movaxcvybu - o920ing 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 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 through each re u92- cybav0oxsistor at the instant shown?

  08.50:. An infinitely long solenoid passes through the 5 uror7 k7cl(ecircuit as shown. The magnetic field of the solenoid, directed into euro7crl 75 k(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 planw( q g3i6+ rxl*9mysk ia1w;lge 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 bulbs of resistance R in it and an ideal voltmeter connected to the corners throull w3 w gsrk*gi;x9i6q a1m+y(gh the center of the loop. What is the magnitude of the voltmeter’s reading?