94.20: A magnet is dropped through a vertical ccy;e9p)wed7ld 7 w6 is)-x ykkopper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magnet in the pipe fpiydel ;k)se c9yw)w-x7k7d6 alls:

  01.30: Lenz's law concerning the direction of an induce+w 2sl cyqe0r1ktu87 nd current in a conductor by a magnetic field could be a restateme2uts71q r0 +nlek8ycw nt of

  11.25: The product (3 Teslas) × (2 meters) × (4v q8ax,cg8n u2kv8r+n meters/second) is equivalent to which one of the followingna,8rgk q+2 cv v8nx8u?

  04.34: A square loop is placed in a unifor0i)lo09x : ghghjv,xwm 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 stvh ,x9 :lw0h )jixo0ggrength 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 theqs. : guv:;kg (4o3 wuce1yp5vh/chnk page. The wire experiences anc/ s3n: (4h :5.kywvoqvug1egp;kuh c induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic fiex5d 8.j9j.w0dzzk ekoerelb f 1n4 e;6ld and experiences an induced charge separation as shown. What is the direction of the mag;60b kkwde1xeen.fe 9.4lr8zoj 5zdj netic field?

  05.33: The figure below shows a bar moving to to ww: t*. xnm)h9tak9bhe 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 conducting kbhaw*9o 9xttmw: .)nrails?

  00.10: When a wire moving through a magnetic field has a voltage induced b v )mhd f).h*x;xwfrddl,j7)oetween ther,)f ;hv.xddljf7*) o)mdhw x wire’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 velocity gle 4s ;v47ihx0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What i;4 ilvhgxs47es the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its opening yav0xhyo;ubx k,a 7:8juya /,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 coming out of the plane of the page, decreases uniformly in time at the same rate for each circuit. Rank the circuits for they; a87x:y,jv hb axa o,0ky/uu brightness of the bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (wy uvvps+ :4lk;*cl yi-hich are assumed to be close to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galvanometer need iucv+y:sll4* yvpk-;le in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet is held ve ;vu/+zmm6tm )7c tmkwry close to the opening of a solenoid as shown in the diagram. As the magnet is moved away/ uzk;m+7m cm wt)vt6m 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 variablejpeosgmf5j/p ,zv0 ,+ resistance in the circuit on the left is increased at a constant rate. What is the direction of the magnetic fiel/p 0jpem s,+jfz og5v,d 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 soleno8/51bxnen pgfid 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 solnf b5/18gpen xenoid and which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular ljdmp8226 hkq yoops of resistive wire are placed next to each other as in the figure. The circular loop on the left is connected to26y phd8kqjm2 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 the figure from above)?

  11.41: For the figur +wsuzag kz6l(hg 4 ;63reg;hqe 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 o3,) ,gi.(v/a oebce gu8axra 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, conducting wire loop sits in a plane perpenhi e2 n53ivcc/dicular to a spatially uniform magnetic field pointing into the plane of the page as sc c2/ei niv5h3hown. 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 to *00 ta ctnze1la wire with conventional current direce*z0tat0c n1l ted 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 occurs?

  17.35: A metal bar is moving to the left across a set of frictionless conductin.scy 6)6 ;ddvbb,axw pg 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 ident6a)bwy. 6pd, d;bsvcxical. 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 throulsk/(k5 tso.3sy+ fcx gh the circuit as shown. The magnetic . fo3y5 ss(sktc/+lkxfield 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 decreaswjp/+-hy: 7m pd/nw,f1b 4cxl s(ghjqing in time. A constant emf ξ is produced for the square loop enclosing the field in the figure. The square loop has three h,j /xgcp+:1 fn mds(lwj- yb4h/qw 7pidentical 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?