94.20: A magnet is dropped through a vertical copper pipe slightly lar2c trzvpgmnf1+i o7,.ger than the magnet. Relative to the speed it would fallfczg,+2vo7tp1. n ri m in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an inducc 6ac,ig5ob tj 3e)-fyt9u 1reed current in a conductor by a magnetic field couldj9geau c,cbyr5 o36i1ttef) - be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meterx,b vha6zpd5*,axb 0cs/second) is equivalent to which one of the followih ,ac6xxbz5bp0vda*, ng?

  04.34: A square loop is placed in a uniform magn 1tbdxp01w/ xu9er8 zwetic field perpendicular to the plane of th1petx8/b9rwu z1dxw 0e 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 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 j1 ay* f1eb/bminto the page. The wire experiences an induced charge separation as shown. Whiche a bj*bmy11f/ way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and experiencesnf,nagne5 0 *u/qs(*vw.eijei+cy(q an induced charge separation as shown. Wig (a+svee*eqnnny .w* u5,f 0c/( jqihat is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on two conductinvn-k )7qry 2y /synx(kip/9 e)w3kz elg rails. To make an induced current i in the direction indicated, in what direction would the magnetic field be in t y /9r2iz7)nekx3yvs -n/lqkye wk)(phe area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field has a voltage induced bek0zi+b8oi5g xf di m/2tween the wirz bd5gof m2i+xk 8/ii0e’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 0tlm 3ifkbvm3. r1, o4d.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetto3.d4rmlbif km, 13vic 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 that ittywi/ xulj8i8bh kc4 b1b-d9 3s 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 the circuits for the brightness of the bulb labeled R1 from brightest to dimmest y jwb1i hu4k3di-c8blx9/b8 t.

  07.34 For the solenoids shown in the diagram (whichlgxkz ,r/rk,5 are assumed to be close to each other), the resistance of the left-hand circuit is/k,gzl5r ,rkx slowly increased. In which direction does the galvanometer needle in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet is held very close to the opening of a solenoi,fcc zf,lp0t0b:xx i;oizs:gt1 db: .d as shgp0tbi ftxsdb:,o0zc1,iz; :fx l .:cown 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 induced current?

  09.37: For the figure shown, the variable resistance in the cngp5jl co85g(ircuit 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 w og(58jcnlg p5hat direction is the conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magn94ru/5kco k p r1,prrtet is 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 of the force on the bar magnet because of the/ p,cur5rptk14rk r9o induced current in the solenoid and which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops zo 8u4w xgms-u ,54 cl 0p: ;-yvsr*yrsuj.njrof resistive wire 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 c5;.ur44ny0 8s-r vmjyc*jr uwsg:lxz,p ou s- enter 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 showni:4p;mh kpu/ g, 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 variable resistance of p873gcxc1 da vthe 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, con,o9j u et* 7la-v-y;gserr( ffducting wire loop sits in a plane perpendicular to 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 r gevty- lja7fu,s9e*- frr;( oesult of this field increase?

  16.47: Two small loops of wire are located c4ilsdmh0e(qt a:+v 2cvz0zs 6 lose to a wire with conventional current directed up the page. A scientist then moves thd s0iql6 cz:4ve +t(mvh0 za2se 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 150m x4+sea(awz ty4ln 9t krsacross a set of frictionless 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 identica+a ta1(5sz0 ekmnl4rwyx ts9 4l. 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 ciru4 qdnn8 4* +yb k(v/ophr/diocuit as shown. The magnetic fi /yo 8i4/*(nurvkq o +h4dpdbneld 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 t.dh.u09iycy8 0fc .oqd wqz8 hhe page is decreasing 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 ano.0yqyw hhuzic q. 88df0.cd9 ideal voltmeter connected to the corners through the center of the loop. What is the magnitude of the voltmeter’s reading?