94.20: A magnet is dropped through a vertical copper pipe slightly larger tha9x da:so.z7h nn the magnet. Relative to the speed it would fall in air, the magne:hz ns.9d ox7at in the pipe falls:

  01.30: Lenz's law concerning the directg7bs.y/x/ewi ion of an induced current in a conductor by a magnetic field could be ayxe.i/ w/b 7sg restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 my2i3 bs-0idn. e nzxe)eters/second) is equivalent to which one of the followin)x z dib.e-3e2ysn ni0g?

  04.34: A square loop is placed i.kxt+. xf l vl7bpef5-0xsl, on a uniform magnetic field perpendicular to the plane of the loop as shown. The loop7xbe lt,vxp0-fo. l + kl5.fxs 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 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 field directed into the page. The wire s ,mu2zhzpdtd0zm73 * experiences an induced charge su3*h7dm 0pzdmt z2z, separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic fieldnd85ig i4fq +sokrz,6ph.i(hd4p g 4i and experiences an induced charge separation as shown. Wha4d,64i hd girgsf8 kh z4i.in+pp qo5(t is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on two co1rr0k v syo/+ml/v/r qnducting rails. To make an induced current i in the direction indicated, in what direction would the magnetic fiov//0l1mvs/+k rqry reld be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field has a voltage inducogli ao b sgsl+090b go3m:*d1ed between the wire’s ends, that0s *a:9 d obsoll ig0bo31g+gm 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 trdah2y2 ydo(r9l. p;x qaveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potentiy q2o9l ;.xrd hpy(a2dal difference induced across the rod’s length?

  04.42: A solenoid is oriented endjcy ;e5, t)yju-on so that 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 )etu5,ycjyj ; 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 8o5p+nbki97 pkiqjl3ru;e gjjt m021are assumed to be close to each other), the resistance of 5+ j ijlktu0ge2i9p3jp bn7; oqm8r1kthe left-hand 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 o l-.i+vys zl/held very close to the opening of a solenoid as shown in the .-slvlyio z+/ 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 because of the induced current?

  09.37: For the figure shown, the variable resistance bmvwebg a20// 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 directiobvawb m/2e/0g n is the conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is held very eu5 ad52mce -k -/vboed4qj -qclose to the opening of a solenoid as shown in the diagram. As the magnet is moved to the left toward the solenoid, a conventional current54ed-aqo2km/ ju ebv-5-qedc 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 to each oths vd4 pzvjh0rm5kpe46 *2ml7rer 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 7j0pmhvl45k*zs 2vep4rr 6md 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 variable res(* jr td4kxn a0p;v+cbistance 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 (j7 (h kvx6n.zy )ilgay56e)p s,msszshown, 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, conducti hkntbf/ 02eu ( bq, ivvrth9(in6)ov6ng wire loop sits in a plane perpendicular to a spatially un 9b q0bi( hv)t/(nhv66ontkuf2v, e riiform 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 wtc)ne5di uw x/r(zo(;y :cp k3ire are located close to a wire with conventional current directed up the page. )(yo3(e5zcirduwnp ; t /kxc: 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 occurs?

  17.35: A metal bar is moving to the left across a gcjt :o;zvj f+ z( 1wg5y3e*ogset 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 resistor:+( z*j; f5oe1 w v3cgzjgtygo at the instant shown?

  08.50:. An infinitely long solenoid p p/by qz n3+7a*tn/dmtasses through the circuit as shown. The magneti/ *q7 ya3zpbmnn tt/+dc field 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 directed into the plane of the page is de( f,b zl1,n3ushe q (l,qea8stcreasing 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 through the center of the loop. What is the magn b8zsq1fq,ll,h s,t n(ae (eu3itude of the voltmeter’s reading?