94.20: A magnet is dropped through a vertical copper pipe slightr7 a mw-mqx:o9ly larger than the magnet. Relatixo: rw 9m7-maqve to the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced curcvvhn.o q; ekie*i:3( rent in a conductor by a magnetic field cooh *vq (v iieek3;:.cnuld be a restatement of

  11.25: The product (3 Tesls;hvrww8cx 3/wl(3jp 7epd 7n as) × (2 meters) × (4 meters/second) is equivalent to which one of the 3p8 drv e/j;xhwln w7pcw37( s following?

  04.34: A square loop is placed in a u ol. ju9m7 nw.7wg:pzk+dj ,a oai0j-fniform 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 strength of 2 T. If the loop is rotated thro .,wz0ljojj.maad- u wgk+n:9fp7 io7ugh 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 magnetk (ta9,dz nor:ic field directed into the page. The wire experiences an induced chraoz:k9, (d ntarge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and experiencqze5io *-t2 djr4rrj df ,)u4les an induced charge separation as shown. t-j,djdrr54 *qofrie ul )4z 2What is the direction of the magnetic field?

  05.33: The figure belo,yl : v6-2c-lckqivm ow 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 t,2y:mli o-6v -qk lcvche magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field has g4 (6dnt w36llfr9zq za voltage induced between the wire’s ends, that voltage isdl 6t r4qnf36( gwlz9z
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 *w58ei: d ncc k+m5 ebhax+ppw13mf/hm/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potential difference induced across the rod’sxhc/we 35 +mpwid1cf+mh a5:pn e8*bk length?

  04.42: A solenoid is oriented end-on so that its mp.lz, ji*vvs05pwt:-fa n *aopening is perpendicular to the circuit containing the two light bulbs as drawn in figure C1. Forn zfs* 5appa-ij*vm:. 0lv tw, 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 diagram (which are assumed to be cl(p qc2pe;bv*aose to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galvanometer needle in the right-hand circuit move in response 2veb qp(p*; acto this change?

  08.29: A strong bar magnet is held very close to the openingun -l mlc.q7ekp7na:c(a/ sj+ of a solenoid as shown in the diagram. As the magnet is moved 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 indun m qkesuc: +a. j-pc(7ll7/anced current?

  09.37: For the figure shown, the varir)7maz ; v/exz59yimlable 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 conventiev r/z ;)ayzixm95m7lonal current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is9np+ip sa5-bj held very close 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 pj p9-b+a5sniof 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 wi.q u8,ma svd;pre are placed next to each other 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 ld8sq, pu;m .vaoop (as viewed in the figure from above)?

  11.41: For the figure shown, the variable rlx ,de 8im;sz(dgexc *k09kh 8esistance 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 resiswp2(f4j (r tgdtance 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 perpendicular t4zh32 i) p0fa *xhpynko a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strength steadily increases with time. Which one of the following effects best describes the result of this field increasep)0ak 3 ny*x4zhhfi2 p?

  16.47: Two small loops of wire are located close to a wire with conventiona: 7g32m, i5h xggn su3wuil0hjl current directed up thhjg5wx7l0: gs2 m ,iu3n ghiu3e 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 conduirwr+*.*u murr)p q xj,url42cting 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 x, urpu)uqwm lri*j.r*+2r4 r the magnitude of the currents through each resistor at the instant shown?

  08.50:. An infinitely long solenoid paqbp3/ 1h)brko q45m qjsses through the circuit as shown. The magnetic fiemkb/qrhj3 )5q41 o qpbld 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 decre yn :m(u:wg5reasing 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 in it and an ideal voltmeter con uy (n5mre:wg:nected to the corners through the center of the loop. What is the magnitude of the voltmeter’s reading?