94.20: A magnet is drw,um/iz5hqlc(5 o c*jopped through a vertical copper pipe slightly larger than the magnet. Relative to the speed it would falq jo5,/z( 5clmu*hwc il in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced current (yr jb0q*1cdhx ta(1o in a conductor by a magnetic field c1a 1jbrdh 0y( ct(*oqxould be a restatement of

  11.25: The product (3zk xpmlw+69e n,it4x6 Teslas) × (2 meters) × (4 meters/second) is equivalent to which one of the followp xt,z64elwmi x+6nk 9ing?

  04.34: A square loop is placed in a uniform magnetick/h+vh,b kfl2 field perpendicular to the plane of the loop as shown. T,f2bk/+l vkhhhe 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 the page. The wire 19;ot,uo cstp experiences an indutto1;9s,p o cuced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magneb9 e)nb4krkx wkay /7;tic field and experiences an induced charge separation as shown. What is the directioxkyerkn); 4 wk7/ bb9an of the magnetic field?

  05.33: The figure below shows a bp av2fr.h.w mf4ci ,od9tbk5 /ar 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 area cowp fbi92,f/rdt4.. 5kc hmavontained within the conducting rails?

  00.10: When a wire moving through a magnetic field has a voltage induced betwe/jf.wncdz 8 (zen the wire’s end8dcj wf/nz (z.s, 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 x34 lxcyth9 1tk4 w7yzvelocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendichz wkyx4347 x9tl1t ycular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on sbjbm09c1/ lcis byia209v0( frf e8ug o 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 coming out of the plane of the page, decreases uniformlycf mbbae(lj082y9 9f cbir/igv010s u 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 d brdv23 qark5:z+9j3q1bx ro wiagram (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 ci do3 bbz:vw +3r2r1r jq5kqxa9rcuit move in response to this change?

  08.29: A strong bar magnet is held very close to the opening of a solenoid as sv1d j fu-2*gj,8vfnywhown in the diagram. As the magnet is moved away from the solewd,j*y f1v2n -gf8vjunoid 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 vaa*.kee i woooj: r:/xe o;9ri,riable resistance 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 dir wo,i o9:*;/ kx:aeeieo.rr ojection 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 solenoid vugz62zu/ k6i)gkyp .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 direc2v6gzug z)u.ikyp k/ 6tion 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 other a e6yk d8p 1 kq**vdcr6kkvv7/fs in the figure. The circular loop on the left is connected to a constant voltage source V. The resistance of this loop e 8vvqkdkf 1d *yckkv*p76 /r6is 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 figure shown, the variable ratz)o3 r13 uwkesistance 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 innercircuit 3n0m. zr6 ncmv;8ss47fuhzq s$R_{inner}$ 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 wzp+grhw-58 . jyuu:d-w/ym k*h2zw 5( aoqt fa plane perpendicular to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strengthwaw5wtu5zfw dyyqu(*hg.p2j+ho8/ mr:kz- - 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 a wire with conj -sdq +;//aep+ huy(5imnz f33 bktmqventional current dire f/ n5p+/h3zutqiqm-eakms3d;b( j+y cted 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 friction cowb-2) pgi4gless 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 currentp-)4cgwog i b2s through each resistor at the instant shown?

  08.50:. An infinitely lsp 11rx4o(yz 4o,yc0m4 sv3p7 dqup ,mu4zl fgong solenoid passes through the circuit as shown. The ma7yx0,14 43v(uzq mpoy ssg4lzpd ur f,cm4op1gnetic 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 75gy4mp9m yjqi,f s0aof the page is decreasing in time. A constant emf ξ is produced for the 975s, y4gqa0mpfmji ysquare 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 magnitude of the voltmeter’s reading?