94.20: A magnet is dropped through a vertical copper pipe slijq3t3 tyd ncym3o 4/*hghtly larger than the magnet. Relative to the sp3t tyd n433/yjchqm*oeed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced curre+e4 . lptph+erh 8mzs/nt in a conductor by a magpze. lst ep+4+m h8hr/netic field could be a restatement of

  11.25: The product (3;t.mnbrve51 b Teslas) × (2 meters) × (4 meters/second) is equivalent to whrbn; t.ve m51bich one of the following?

  04.34: A square loop is placed in a uniform magn v8 7bu ya -zg6byp4m)bdr0 y)zspg,v5ivkj;5 etic 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 rotatd8ag ub 6 rkvgmbyp)yp-y,vz5s z0; j 4v57ib)ed 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 the page. The wire bd4usnms3ja(.7, cj, 7 s llbl experiences an induced charge separation as s4sa, jlc37bj(bnud,ml . l 7sshown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and expef,tw78yxf;k w e;wm,criences an i kewcwfx,8yw7f;;tm, nduced charge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a barsc1oiwr xq ;0+1mhrjj0 8tw+p moving to the right on two conducting rails. To make an induced current i in the direction indicated, in what direction would the magnetic field be inmwh1i0rrxsjj 08+otp+cwq1; the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field hapo-rf* f /97yf5exyp ws a voltage induced between the wire’s ends,ye yp9f-7o px*fw/f 5r 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 travelingaag+r 46*.vhjsr4lebcu1 ebhqf1g 3 3 through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potential dif1er3ub4 a 3gb av+6h*c.4sq1gferljhference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its openingp g-of w0s6(fi 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 ofw-ig (pf6 os0f the bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (which are assumed m;v x20c:yrd 8cy gcz8to be close to each other), the resistance of the left-hand circuit zv2;y:c0g yc m88rdcxis 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 solt uq.b d7:hfy 6z0w-fhxme/8lenoid 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 oftb zedmw0/h- 76yx:h8 ff.q ul the induced current?

  09.37: For the figure shown, the variable resistance in the circuit on the leftmnnu-m.bda,(x -ey2n/ u,ui h is increased at a constant rate. What is the direction of the magnetic field at the point P at the center of th nnd.eh,na 2-u/iuxm m u-yb,(e left-hand circuit and in what direction is the conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar ma:5, s 8-znkwjl)apxtbs+k ,yhgnet 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 induced current in the solenoid and which magnetic pole does the “??” in the diagram rep-5l8k ) yhskw+xn b,t:,jzs paresent?

  14.34: Two circular loops of resistive wire arkot34lovah t,n*p; :k*p rwr4 e 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 th4*:,o opkvlnkrpt*t 3r;wa 4ime. 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 figurex pg q-*.myuw ,x,bni6 shown, 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 in7id1:ipxdwsny w6jlp (.d(.t xdx00qnercircuit $R_{inner}$ 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 to u zf23 ,sch.jpa spatially uniform magnetic field pointing into the plane of the page as shh2p juzc3fs, .own. The magnetic field strength steadily increases 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 wi0szap dtva7(1re with conventional current directed up the page. A scientist then moves7d a0aps 1vt(z 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 aob r8wmtfz r eb8sznjb-i8*k/1zp 8,3 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 of theib8z/p1b8s t8k ownb8j zm * erzr3f-, currents through each resistor at the instant shown?

  08.50:. An infinitely long solenoid passes through the circuit abvmy.blhv x6q0i9) l ,dlr8fq3 4c0zts shown. The magnetic field of the solenoid, directed i)i r v8ql0hy93x vtzdl.,c46 mb lq0fbnto 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 the7 r0vxtgj5yv : 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 ittrv 5v:x yg70j and an ideal voltmeter connected to the corners through the center of the loop. What is the magnitude of the voltmeter’s reading?