94.20: A magnet is dropped through a vertical .d61hmf4 r 6zbt /8updwt5k zjcopper pipe slightly larger than the magnet. Relative to the speed ip m665utd.rt4w1kh dbjz 8zf/t would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced currgc;oxvw 5 bc w 7j3v;l15ph-hpent in a conductor b5l;3poh15cv p gb7- ; cvjhwwxy a magnetic field could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (tmo vkc 1r/8)8 *ml1.pau cynv4 meters/second) is equivalent to wh rm)ctvck 1y*ov.u/ 18pnaml 8ich one of the following?

  04.34: A square loop h e,;d5p3gehd is placed 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 5;d ,heg3hped 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 fis38osge lile k fy*l3 66,*nyqeld directed into the page. The wire experiences an induced co86ln,l3*i ql6kysfe*yg e3sharge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and experiences a/h9 c9g)( nelr/jzeii n indu / lhig9ce/ji(nr ez9)ced charge separation as shown. What is the direction of the magnetic field?

  05.33: The figure beml6.p gf0fau)lbx ies 3v86e( low shows a bar moving 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 conductlfg8aie3p . e0(ulxbfsv)66ming rails?

  00.10: When a wire moving through a magnetic fil *yakhb w5nzj5c85j3r 9 gqi9eld has a voltage induced between the wire’s ends, 5gq5y3 9i8wz j*nr59bjakc lh 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 velocity 0.30 m/s traveling throughf 9 o49x boh+n2hazhms;)6hpq a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic fifh4p9nq hs x9 2hb)o+;z6oahm eld are all mutually perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so n2z,unbz+k/ kthat 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 n+z b kz2un,/kthat 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 m:1 ug/zxanlf6)hnq0the diagram (which are assumed to be close to each other), the resistance of the left-hand circuit is slowly increased. In whauh q6xz n)m1n/ gfl0:ich 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 ce1oq,rwmdk + yxlk6bfb)i568lose 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 f k6l8 1ebxdkq)mb 6w,r5+iyoconventional 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 show4. u ,knga4us f191hto ih3jqun, the variable resistance in the circuit on the left is increased at a constant rate. What is the direction of the magnetic4nj3.9ofqhush gikt41 ,u1a u 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 vexr.qzap6 e:yv 3jgt tkt m.:+/ry close to the opening 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 directez qjge: m6xa3p. tyvtt r+k/:.d 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 loo:) 3 hd p(r5ms zbauoi.1)oq7bewtiu7ps of resistive 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, wh rq5pz1smiau(ed3 bbot 7o.h) )u: wi7at 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 shp/x3z k;vf j 46-zoeueown, 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 shown, the variable resista2(p.tn1 0bw p)e1skuccwevkm fn*/fa j0 kp55nce 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, conk po-1)ogj9dsf +vvx.q q: 6jpducting wire 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 o.v-)jj:p+vskdogq1 f q px9o6f the following effects best describes the result of this field increase?

  16.47: Two small loops of wire are located close tovt3luz - 5n(tb a wire with conventional current directed up the page. A scientist then moves the loops away from the current as shown. What is the orientation of the conventional current in each loop while this z-tu(5b3 tvlnoccurs?

  17.35: A metal bar is moving to t:(71c ual+hkhx me0nwu52hp qhe left across a set of frictionless conducting rails as seen in the figure. Throughout the region betweenh:ehlh (qanm pu057cx u+2 k1w 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 resistor at the instant shown?

  08.50:. An infinitely long solenoid passes bj5odf,9l lj( zm- o.pb9qkc s:tpe (7through the circuit as shown. The magnetic field c9kfmesoplj -.dzt(b b5p:jqo9 7(l,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 direm)gjidofr-j:t7x8 p a:bl7fzaj, ;) qcted into the plane of the page is decreasing in time-) f8a,z7pbrjqfogt; j 7a: lij:m)xd. 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 through the center of the loop. What is the magnitude of the voltmeter’s reading?