94.20: A magnet is dropped through a vqtt kkkodbvo )it,1j2n.+8a32 h kr8zertical copper pipe slightly larger than the magnet.b )to3 kdv,jk oqza1tn8 hr.t+k82i2k Relative 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 current in a conduct-43/1jd v :df/rdt hueop7r fmt eh*;vor by a magnetic field could be a restatement 4o ;1-ter hd d v73ejvtdffh:/p*rmu/of

  11.25: The product (3 Teslas) × (2txw8*upy:dd,/j o+ 1r:-qi g yjr ea/p meters) × (4 meters/second) is equivalent to d,p8e /ajrdgx +:ytr:j-ioq/ *p 1wuywhich one of the following?

  04.34: A square loop is placed ir *omavbpv)l/* 4tzh0n a uniform magnetic field perpendicular to the plane of the loop as shown. * a/0o btz4 hmr)lpv*vThe 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 q9hn n.jw9w sr/2nhcn;h :jh6the page. The wire experiences an induced charge sepah2nhwqh 9njwn :6.cj9sh;/ rnration as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and er5-dtql p;0 fuxperiences an induced charge separation0lqr ;d5u fpt- as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right og9 fxhp)0oh7zc*u l sbj/y.m6n two conducting rails. To make an induced current i in the direcu7)yl p.*6z9m/j hco gfbs0x htion indicated, in what direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through 308nh4om4k)nvr chv4t/j e bw a magnetic field has a voltage induced between tkcn4v 4n/38h v h )0e4bomwrjthe wire’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 0.30 m/s n4u (vz 2lknlkslz)yaes-*-; 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 thelvzae (lsu 4z)nyn-l-*k2 ; sk rod’s length?

  04.42: A solenoid is oriented end-on so that its open: 4p p2xufhu-b1sk4yf ing 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 yxpfsuh-1bp:4u2 4k f 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 solenoih/ 5:2i )d(oyppvsvryds shown in the diagram (which are assumed to be close to each other), the resistavdph/:ov()s5 ry yip2nce of the left-hand circuit is 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 h z f6a 0r4ys +hrz,w i(sv63rwb2tiz+seld very close to the opening of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid at constant speed, what iw6 rrzfbv6r4z,t s+zw( hi+s0y 3ai s2s 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 t+bq0 pv2*gsb pw .ck4;tmm(8 z;zkyughe circuit on the left is increased at a constant rate. What is the direction of the magnetic field at the point P at the cente gsm.ky v8gwb4b;t0z+u*2;pc (z kmpq r 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 close to the opening of a sj0);ta+h/cwm1nhunf i+e kh7,v d9 p dolenoid 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 does 0 +kfemht+ p1j)udwnv9n7daihc,h/ ; the “??” in the diagram represent?

  14.34: Two circular loops of resistive wire are plm9o t8k2wpagpi7q 9b h7o a;r0aced 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 resistanceoa7pm w78r0 t h99agb;ioqk2p 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, zr (bvm 1l(qbm6 2fvp: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 the innercirc/vk2zwxd1 4a,yf*ndt uit $R_{inner}$ 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 perpi.ocfxzi 7sysl.6 o. 9endicular 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 i .so c..o7zix f96yslthe following effects best describes the result of this field increase?

  16.47: Two small loops of wire are located close to a wire with conventional cu wm07t9-i.9 bs vmx6mvzj w9msrrent directed up the page. A scientist then moves the loops away from the current as shown. What is the orie6jv. mzm m9s07txi sw-mvbw99ntation of the conventional current in each loop while this occurs?

  17.35: A metal bar is moving to the lefw4prv* vud x0htz;1: et across 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 identical. Which one of the following choices correctly indicates the direction of the conventional current in the resistors and the relation between the magnitude hdz*0vu ;ev twx p1:r4of the currents through each resistor at the instant shown?

  08.50:. An infinitely long solenoid passes throrcdo6 +(, +p ;h.kmyxpl xjgf5ugh the circuit as shown. The magnetic f+j6 xkog,( lpmpxdfhry5+;. cield 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 in e wd/v,xn1on /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 through the nn/ed,/wxv1 ocenter of the loop. What is the magnitude of the voltmeter’s reading?