94.20: A magnet is dropped through a verticasi3uw t.(vd*b l copper pipe slightly larger than the magnet. Relative to the svt(wb* i 3.sudpeed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced cjr2k- a,,0e uu ncoqr4urrent in a conductor by a magnetic field could be a restatemenreq0 kac ,ju,2u4 -rnot of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/secondc7ds e a1m;x-a zehw2 lm:7sf0) is equivalent to which one of the foll; xcm2a7sd7lh s10ee:w-amz fowing?

  04.34: A square loop is placed in a uniform magnetic field perpend4 gxtm- ;zrm wl-ft++picular to the plane or4;wf-lmm+ ttxpzg +-f 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 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 x+d4- mni +okr7)n7(dsd spvw the page. The wire experiences an induced charge separation as shown. Which way rm -sp ni7nd)xdo+ swv7(4 d+kis the wire moving?

  00.20: A wire moves with a j:b+l 4ek:y jvvelocity v through a magnetic field and experiences an induced charge separation as shown. What is: 4k:ej v+yjlb the direction of the magnetic field?

  05.33: The figure below shows a ba+qx5y 1djzya 9r moving to the right on two conducting rails. To make an induced current i in the direction 5dy+ qj yx1z9aindicated, in what direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetisj,gefv.v pg 4 zs/0kd, o6e1(g dkf /ljj*h*nc field has a voltage induced between the wire’s ends, t 0/kd/svjsgh*j( , kl1ndzf.p *gvgje64 ,feohat 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 3x wq h72pmw5fd, le2ehas constant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060ew5fx 2e 7m2h,d q3plw 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-v5u2 hqxn de67axmqp6r6 2 d4v y fs934h7yjxdon 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 resistance is added as shown. Assume that the magnetic field from the solenoid, shown 65v9p 427u nahqxx4xer67 26vf dqmdy yd3sh jcoming 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 t7wzd;b+ z 3rptn qr.m6he 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 galvanometer needle in the right-hand circuit move i6.tbq nzdpm;+ w37rrzn response to this change?

  08.29: A strong bar magnet is held va 9+l 3efdysj4-1ey jiery close to the opening of a solenoid as shown in the diagram. As the mad i9 1yes4eljf jya+-3gnet 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 ut4xkkw7 6(nk 47*h hbmc,hyiresistance in the circuit on the left is increased at a consu4b4m,khkh x7 c(ih w *6tk7nytant 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 conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar mj oez2-h3x5 a(e8fyg 2dnsyd5agnet is held very 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 directed from A to B. What is thna5 g2se(ed- yf5ox 2zj3yd8he 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 wirh5c 3 vz,lp p//bvznz(e 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 cp /v3(n5zczb ,lzvh p/enter 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 va-vd0r;afh j 2qriable 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 innercirkov,t1.ntct n,9q0 4 v,ag(gmira q/e r m)lh;cuit $R_{inner}$ 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 perpendicular; t 8 wemzr0(mo14;qt3pmnm fo to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strength steadily increasmf3(ep wt84 1tn ;mmromz0;qoes with time. Which one of the following effects best describes the result of this field increase?

  16.47: Two small loops of wire are lo3jpzq)f8 ok 7mcated close to a wire with conventional current directed up the page. A scientist then moves the loops away from th7 )kpq jmz8fo3e 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 frictionzzu p++x7trp+less 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.zt7u+ +x rp+zp 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 pass-)-ldpbfu, g nes through the circuit as shown. The magnetic field of the solenoiflbugn )p -d,-d, 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 int9t q72u0ylq.lj/et iio the plane of the page is decreasing in time. A constant emf ξ is produced for the square loop enclosing the field in the figure. The2 qlqtey/ 9ju0.i7lti 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?