94.20: A magnet is dropped through a ver.5jzdg upcg,egp.; s*y)ex 8i tical copper pipe slightly larger than the magnezx8de*s).gu p,yie5.p ;cgjg t. Relative to the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the directi+lw. fx2h8rs kon of an induced current in a conductor by a magnetic .+2xsk l8hr fwfield could be a restatement of

  11.25: The product (3 Teslas) ×26c8 0if*hu s 0dx4tr+usxp,bmhoh (z (2 meters) × (4 meters/second) is equivalent to whm p(0tu8 dx+ihfzb40xshr,uoc6*s2h ich one of the following?

  04.34: A square loop is placed in a uniform magnnez5amd 4:qa2 etic 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. I45zq2dean: ma f 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.qg+*jpsfou*c-.1 bs txsp8 0y The wire experiences an induced charge separation as shown. Which 1*o gjyssb qx fsu*8t.pc0+p -way is the wire moving?

  00.20: A wire moves with a 8 ybq8movd9 6xmu6al 3 0hn-mlvelocity v through a magnetic field and experiences an induced charge separation a n6 uayl ommh8-6l9xm3d8bq0 vs shown. What is the direction of the magnetic field?

  05.33: The figure belo-dp 7gx5lr6j7vjfb 7qok dezf/ 1f0j7 w 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 areaxj6or/-b7egqfp 71k fjv0l7 f 57 ddjz contained within the conducting rails?

  00.10: When a wire moving through a magnetic field has a voltagew .h94qb-k eno induced between the wire’s ene 4h w-nk.9bqods, 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/4z0q rp3dz/+s bpjh7as traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field as0hd+ pjbr 3/ pq74zzare 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 i/qat:ymq 0pq/9ewt3 qs perpendicular to the circuit containing the two light bulbs as drawn t/w9eqt y/3p0 qq qa:min 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, 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 dia/r4ja1fe1hwpf pd 9 h m/6j:csgram (which are assumed to be close to each other), the resissc9: mhahw1frp64/ e/1dpj jftance of the 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 held very close to the on,xzxwp ex6cyc) +o+vue6rcc /b1 ;4 upening of a solenoid as shown in the diagram. As the magnet is m r)c6,61n 4 wx v+eu+z obc;xcu/pecxyoved 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 iqc2nq.2t :z.8o(grz2cm q(v h8x ylxqn the circuit on the left is increased at a constant rate. What is the direction of the magnetig(2q2m yqlxr no 8cz(h.qx.vz:t2c8 qc 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 openingpa;t u;yim3/ubj0 q91iyvbx-; sn,p e of a solenoid as shown in the diagram. As the magnet is moved to the left toward the solenoid, a conventional yu9y;bxnsv i;0qbe,t3-u;1 api/ jpm 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 to each othz+ 1dobw6sm* jmk qc ,q;r:cn/er 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 ts mjr ,c6+ wd1nmqokz/*:;b cqhe figure from above)?

  11.41: For the figure 8lgdc1 t2wz t)shown, 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 resistance of the inasj :-y ac2) vksfh*3gm+m+ gk vj.0smnercircuit $R_{inner}$ 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 to m* : ksz:ni3q/b7tv xz .4rmtta spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strength steadily increases with time. Which one 4 zrbv:/7qz*itm .xtskn:3tm of the following effects best describes the result of this field increase?

  16.47: Two small loops of wire are located close to a wire with conventj5sche.jco3rg. .q e9ional current directed up the page. A scientist then moves the loops away from the current as shown. What is the orientation of the conventional currencr9ge.c.eo3 h5q jj .st in each loop while this occurs?

  17.35: A metal bar is moving to the l. 3r-e6:hb ylchvv;uneft 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 re-:vh ; c.nbur3lh e6vysistors and the relation between the magnitude of the currents through each resistor at the instant shown?

  08.50:. An infinitely long solenoid passes through the circuit as shown.n hif,w zm9g3p50s. c- (+ec3c rl:o5schuqc b The magnetic field of the solenoid, directed inc5h 9q i,cmw hecu r 0(gboc.z+fnls3-ps3c:5to 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 plat nmeym/6 -yza /mktutm.2o85ne 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 -2z tuem/6yt8mmomayt5. nk / 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?