94.20: A magnet is dropped through a vertical copper pipe slightly lxlv* tc (e3t13j3riek arger than the magnet. Relative to the speed it would fall in air, the ma3t31rije *3ktx(vecl gnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced curria*2w m,vt732 t. oy wszz ;eygp5,le3;wae bbent in a conductor by a ms wep zt; 3vyl;ob.t7zeg* bew, 5y2,a3wa2miagnetic field could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is eyksv, cir ypn8;jk9t 07/m(xi -h4+ qokhk j3jquivalent to whinh/j v,-smcr; 4iy t37p+ kxkoh 9(kq8yjki0jch one of the following?

  04.34: A square loop is plaen e pw40nj88( f+qltmced in a uniform magnetic field perpendicular to the plane of the loop as shown. The loop is 0.5 metersn8 8wj(mp+eefqnl 40t 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 througet+lpr2bf .n ,h a magnetic field directed into the page. The wire experiences an induced charge separation as shown. Which way is the w rl.tf+n2,bpe ire moving?

  00.20: A wire moves with a velocity v through a magnettzi /mx ;*o8)o9olgac ic field and experiences an induced charge separation as shown. What is the*/ oc8g l9tz;oma i)xo direction of the magnetic field?

  05.33: The figure below shows a bar moving to the rigy1 uelp5q54i:rjiofq +9ll/mht on two conducting rails. To make an induced current i in the direction indicated, in what direction would the magnetic field be in the area contained wit5p/l: eu59l lrfqyq m1+ij4 oihin the conducting rails?

  00.10: When a wire moving through a ;k mdmp(2rz27in o1tgt/ :sqdmagnetic field has a voltage induced between the wire’s ends, that voltage idq;(mt mgrzs2kd2i : o71/ tnps
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 cx2l y)70(yjs1k e ovejonstant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potentkx0y2ev(s1 jjy) e o7lial difference induced across the rod’s length?

  04.42: A solenoid is oriented en,fv2 x jv. yx9z-swbh:e kp4/hd-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 th/ 9 4jh-febpz kyxv.2s:vw ,xime 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 a)z:muyz:8yzi gs ;8cassumed 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-hand circuiti)zuy8c y:s;m:g zz a8 move in response to this change?

  08.29: A strong bar magnet is held verykqda,fu2pyp)+ i- g* h 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 is the direction, k)*hugpqay +d2 pf-i 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 sn :mzrfh7 57 pjra0(fehown, the variable resistance in the circuit on the left is increased at a constant rate. What is the direction of the magneticf(r5 a0:jmfez 7nrh7p 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 ver- - ,mviwsr8(xs s:gfey 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 induced current ves-ixfw, sr( -s8:gm 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 f5h3whznu 0gx-/zy wh-yj7 )g*rj y9m other as in the figure. The circular loop on the left is connected to a con9jw3gxy-uzhw y m5hfzry7jnh0g*- / )stant 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 loop (as viewed in the figure from above)?

  11.41: For the figure syswtj-47z+(lybs9 r 4u6wivrnfkuji j),q*. hown, 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 iz rb*un-h/ s7wnnercircuit $R_{inner}$ 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 wirzp8j4t*xzbxzj1v 5 a s wln9r-lo.:3 je 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 increaszwrx5 : 9-43xtz * bvj.pj8a l1ojszlnes with time. Which one of the following effects best describes the result of this field increase?

  16.47: Two small loops of wire are located close to a wire with conventionalfzk+dq(i u8.8wr d;xi current directed up the page. A scientist then moves the loops away from the curreui 8xki;w+(rd zfq.d8nt as shown. What is the orientation of the conventional current in each loop while this occurs?

  17.35: A metal bar is moj3kqby; h f+0nb c*3xqving to the left 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 nxh;bfy +jk33c*b 0qqrelation between the magnitude of the currents through each resistor at the instant shown?

  08.50:. An infinitely long solenoid passes through the circuit as shown. The g;g-qu ;edgo p/8 ot.rmagnetic field of the solenoid, .o-rpdue8t;/qg go;gdirected 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 directene7d bs vpy;wmv20 n41d into the plane of the 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 an idealm; 14ve vyb 2nw7spnd0 voltmeter connected to the corners through the center of the loop. What is the magnitude of the voltmeter’s reading?