94.20: A magnet is dropped through a pj9io3+;w tdw1o6 xyd vertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magnet in the pipe fal+tw3 iod; j69 dpw1yxols:

  01.30: Lenz's law concerning the direction of an induced current in a cyiae8 hc; i*5monductor by a magnetic field could be a restatementih i5y;8m*ace of

  11.25: The product (3 Teslas) × (2 meters) × (4 metera5ksmi.w: )o*ewuz76 nk koq8s/second) is equivalent to which one of the5s6ewom.kk*k uziw7q :a n8o ) following?

  04.34: A square loop is placed in a uniform magnetic field perpendic *dfw i;eb7-zdular to the plane of the loop as shown. The loop is 0.5 meters on a side and the magnetic field B has a str;we7 f* z-ddbiength 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 throu1 j; c z ktvcv v;na1y6un1ka+j(:i,8xj/fgbygh a magnetic field directed into the page. The wire experiences an induced charge separation as shown. Which way is th8v11fgby /zk(t;;iu 6vx n1c n:kcy ,avajj+je wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and mp; sv7+d nlm+urq+ r4 pg9x2mexperiences an induced charge separation as shown. What is the direction of thev mur npmd+ms+9;pq72r+ 4 gxl magnetic field?

  05.33: The figure below shows a bar moving )o qiy)jc7)jsorn77rc50b ft to the right on two conducting rails. To make an induced current i in the direction indicated, in what direction would th s7qni0) ro tf)j7cco jy)b57re magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field has a voltage inducedzxd:6jwz / 64rn k)pat between the w/n6zxr at64j: w) pdkzire’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 ml 7cr -e u5w72bc5potvelocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are alcb2ou7pw7r5 5m ce- ltl mutually perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid isb (r eps95ev2 xnbt2,e oriented end-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 shorp2 etx(ev nbe,25r9bsting 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 s sw tn(9 7bji*hysg)aq;(agvz3 wi8j+hown 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 galvanometer needle in the right-hand circui(g yjiji b8a zw3+9a qgvwhst)*(s7n;t move in response to this change?

  08.29: A strong bar magnet is helh8f7 s(gb gyv2d 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 ma8vg(7fy2bs h ggnet because of the induced current?

  09.37: For the figure shown, the variable resistance in the circuite bw-z(xbs 52faea)y5zil;:f on the left is increased at a constant rate.abs:52lxeae)f( y-bwf i5zz; 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 magnet is held very close to the opening of a solwmv5 jj 77s-alenoid 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 the direction of the force on the bar magnet because of the induced current in the solenoid am5- l7vwj7aj snd which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of resistive wire ap+w;-g7d jq,5jelaj aqv9b/hre 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) and what is the orientation of the conventional current in the right-hand loop (as viewed in;-haql j+g 5,ewpqavd79/jbj the figure from above)?

  11.41: For the figure shown, the variable resistance of the outerq-hla-vu e; )e ro;kq h0n)lo; 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 vari7 ++wuxh*zoto able 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, conductinglpfgidad3ikw2oc3,-d7;lw(* fz h;p wire loop sits in a plane perpendicular to a spatially uniform magnetic field pointing into the plane ofcha, ;w -*wdd(;k 32gpiz3f lodip l7f 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 ( xndv0j :8 lgu79agttto a wire with conventional current directed up the page. A scientist then moves the loops away from the current as shown. Whdg89 ul0 a x7tg:vjtn(at 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 frictionless conducti7yhe ok+i 0(ouxs/j k+ 3qxa4ang 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. 7i yxoaak/4u(3h+ +k 0x jeqsoThe 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 pass hhqb fd w5k208)osf1b9 kgds2es through the circuit as shown. The magnetic field of the solenoid, directed intogfhk 8 1dd 52ow)hb bqk09sfs2 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 wni-k18b*ucq the page is decreasing in time. A constant emf ξ is produced for the square loop enclosing the field in the figure. T-kqbiun1 8c* whe 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?