94.20: A magnet is dp+08b(n-c h,rpro gvt ropped through a vertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magnet in the pipe falp v0rh,8 trco(-bgn+pls:

  01.30: Lenz's law concerning theok6nu4wolu9 +h6e rs- direction of an induced current in a conductor by a magnetic fieuoh o4k 6r6wu-9 sn+elld could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/secb81a5kjc4 fwj ond) is equivalent to which one of the followia4jbfw8 c1jk5ng?

  04.34: A square loop is placed in a uniform magnetw3 (: x al;hyr7ot7eekic field perpendicular to the plane of the loop as shown. The loop is 0.5 meters on a side and t:7ohae37we ktr ; y(lxhe 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 m ;.ba6tdoevx 2a sdv-,agnetic field directed into the page. The wire experiences an induced charge sepas6va-bdoxe.; dv2t,aration as shown. Which way is the wire moving?

  00.20: A wire moves with a :cjprh3 ss h+(velocity v through a magnetic field and experiences an induced charge separation as shown. What is thes (+r3hjh:csp direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on two conductinuuv .z. qpe vvuxo183,(1 en ypf;ky)ng rails. To make an induced current i in the direction indicated, in what direction would the ma(.3ye 1v f uunpq,ep.8ky;uz1onxv )vgnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a b8igm:p14tm jy 1w8b zj8m6pi magnetic field has a voltage induced between the wire’s ends, tm4m8pt61 b:gjipi w jbyz1 8m8hat 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/s traveling thp3is( hke) apd6wy5w eb:38rb rough a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field : 8b phrypiw de5k3w36(ae sb)are all mutually perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented bc*e0(rjtyuvr9 w1r( 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 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 thebte9*jwru0r1r (y v(c circuits for the brightness of the bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (which are assumed dz*f8b8 lwn29baj0wq 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-h ql09f 2*8bzbw8nawjdand circuit move in response to this change?

  08.29: A strong bar magnet is held very close to tcjma86u9t v y;v,l gc(he opening of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid at constant speed, whaac, c9tv;yv6m 8lj(gu t 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 *de9)ed ms shg f968goshown, the variable 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 direction is the conventional current through t 9oe96ghd *mf es8)gdshe resistor in the right-hand circuit?

  10.39: A strong bar magnet is held very close torfa*emc4kvx2hxy a i,- 20dmzv2+ k1g 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 thee arvcxfx01 kh2m24,*amydv +gz2i -k 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 other as iqy 92p sev., ggqp.l:t( .tynin 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 .9 l(vqt:n piye.pqs2tgy,g. 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 resistance of the outer circzwagu) 24pp2wcfxq; 74 cvre+uit $R_{inner}$ 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, thep- e3r0 pkk:m z7.djge 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 perpende/ (l ft706ac*ax9fpj brjd y:icular to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strength steadily increases w/ fjf*ac :xl76ya petjbr0(d9ith time. Which one of the following effects best describes the result of this field increase?

  16.47: Two small loops of wire ar3/(zxqqn th3+pxwp 0 ze located close to a wire with conventional current directed up thenz+zx3 pwtq (3hq0/xp 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 movintgut 5,eow(3 wldl 6jd0gg;4hg to the left across a set of frictionless conducting rails as seen in the figure. Throughout the region bet5uogld h3,jtt6w ( ldw 0egg;4ween 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 currents through each resistor at the instant shown?

  08.50:. An infinitely long solenoid passes through the 8-jy cb0zf6wu jx) 5mpcircuit as shown. The magneti-)jwbuj 568my pzxf0 cc 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 of the page is decreasing t za021t2 xcakin 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 in it and an ideal voltmeter connected to the corners ax2ka1c 2t0ztthrough the center of the loop. What is the magnitude of the voltmeter’s reading?