94.20: A magnet is dropped through a vertical copper pipe slightbm 3*kelyt p6w+ym3. vly larger than the magnet. Relative to the speed it would fall in air, the magnet in the pipe f v33mw m.tybply6e *k+alls:

  01.30: Lenz's law concerning tmtl/ h);myg5/co t*umhe direction of an induced current in a conductor by a mag//l )ct uo;tm5 mm*gyhnetic field could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) i.:oi7xrtywt34 gtng; s equivalent to which one of the fny7x:.tw o3 gi4;trgt ollowing?

  04.34: A square loop is placed in a uniform magnetic field perpendicular to thw:8h- /.qvlboo9o fjwe 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. If the loop is rotated throu9-w/8h:j oo fbwqlo v.gh 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 th6(qxeje i4gbx e: 8ne5e page. The wire ex:4 iqjb6exe ee8n5(g xperiences an induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocityqe+br6jo d0gn)j+; sfzw ;p0mmj5 s 6b v through a magnetic field and experiences an induced charge separation as np eg mms)b0jw;jsqorz ; d+66+b5j 0fshown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on two conducting rail -6 fqa,j;mb. /9atr-zc hyopxs. To make an induced current i in the direction indicated, in what direction would the magnetic fieldjxzam; / t6o,f rahcqy9p.- b- be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field has a hvsig. 4x7. mlvoltage induced between the wire’s ei l4gh.7vxm.s nds, 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/s tqc7-(dvd 5b qlraveling through a uniform ma-(qcvl5q7d d bgnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so*eh;vz(k e7 10j3 qn utqnux-d that its opening is perpendicular to the circuit containing the two light bulez0ktnunv-3(eq *7; dqxju 1 hbs 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 the brightness of the bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in 6c3 joxg4mux 7 zy*ey-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 galvanomety4 xm7yj-g *exu6o3czer needle in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet is held very close to t,5 zbukzhc + 9z/7l)ra1ujy fohe opening of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid at constant s f)/b9 h5, 1zj+ cuazr7lozkyupeed, 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,; -jkg:(ac8.2max y*svnf iwc the variable resistance in the circuit on the left is increased at a constant rate. What is the direction of the magnetic (-s.img:c 8cn; yaajkw x*2vf 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 clos lgha1a9 ne.r(e to 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 the direction of the force on the bar magnet because of the induced current in the solenoid and which magnetic pole 9 ena(rga1hl. does the “??” in the diagram represent?

  14.34: Two circular loops of resistive wire are placed next to each other bh9;x6qgq, baas 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 left9qb,xb; ahg6q-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 c;6hgd .3p tfuyiw4, dq5o 8lbrknv2 (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 resis*jtwyu(ath1 e: b jw-1tance 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 perpe8p l-r. yh,-zrb rnos/ndicular to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strength ,.8r sbzlryr -nh o-/psteadily increases with time. Which one of the following effects best describes the result of this field increase?

  16.47: Two small loops of wire)edr4 ndzrgtuh,7 ,weci4, /l;y fk-r are located close to a wire with conventional current directed up the page. A scientist then moves the loops away from the current as shown. What is the orientation of the conventional cur-d,het4fiklygzrr, nec,); 7w4du r/ rent in each loop while this occurs?

  17.35: A metal bar is moving to the left across a sagas)vrr3p9 dsnc2, r h a0-4met of frictionless conducting2gs4dr 3v rmcpa9a,h)-0asnr 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 currents through each resistor at the instant shown?

  08.50:. An infinitely lo nb5 poibb0j pt fklj/v:/ey/ .6;z/jdng solenoid passes through the circuit as shown. The magnetic field of tp5/e0b;l jpin/.j/fd b6/o zj vbtk :yhe 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 o m 9y6-mslomr+qg1o4 rf the page is decreasing in time. A constant emf ξ sq 1 9- ro+o4mrl6mymgis 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 through the center of the loop. What is the magnitude of the voltmeter’s reading?