94.20: A magnet is dropped through a vertical ,nklrd0sjo, 1d 5sdg,copper pipe slightly larger than the magnet. Relative to the speed it wo1knjldr,,5o d,g s0 sduld fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induc qq5xloq +p*1ped current in a conductor by a magq*x5+l o qpq1pnetic field could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second);5b9 ngn5eeqa is equivalent to which one of th; 9qaen5eng5 be following?

  04.34: A square loop is placed in a uniform magnetic field *zhle3b,)lztnsl t6p s,84 tc perpendicular to the plane of the loop as sth*tcp,3e stbs68n l)l, 4zzlhown. 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 ma rq;w.9 c a8afqa.ny2*ms-jkagnetic field directed into the page. The wire experiences aa-afw9 ysk*.qc 8nq2jr .aa;mn induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and experienui4f dk*zjz1b0an5)cces an induced charge separation a4cku0a)f zdnij*bz51 s shown. What is the direction of the magnetic field?

  05.33: The figure below show5zc p;u,hnfw j/ 7dcx0s a bar moving to the right on two conducting rails. To make an induced current zh/cd7u;fwjn x,pc50 i in the direction indicated, in what direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field has a voltage ind7ootb,k 3q3az b3ok d*uced between the wire’s ends, that voltageo t3k,q* 3okzo3a7 dbb 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 co0 3vx7 *wev8 i5z4 :gp1dpkbeaikvjp:nstant 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 potential difference induced across the rod’s v :ka:i0* 4e3jkgvi1vppzx85w p7ebdlength?

  04.42: A solenoid is oriented end-on so that its openica8/ p0o3 ljm6mcx ;cing is perpendicular to the circuip;ima80oxcc l6j c3/m t 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.

  07.34 For the solenoids shown in the hv jw30az2fo ,+h,ilwr 2yt 8gdiagram (which are assumed 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 circuit move inzgohv,firj8a0l 3+ wy22wt, h response to this change?

  08.29: A strong bar magnet is held very closevu ccpv(aumr 95k;*n . to the opening of a solenoid as shmk;*pc ran(v u 9c.vu5own 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 circ8l ppd:vhk 4+ ik,ut cki5c)9zuit on the left is increased at a constant rate. What is the dire8t h v+dc cu4,k9zli ikp5p:k)ction of the magnetic 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 very close to the opening of a solenoid as so0odg6: asje h4g5v.l hown 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 56dgvsg.e o 0l ha4j:othe 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 w61k* b--ejphz2ldkz jb fy2r ,ire 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 loop (as viewed in the f1kj6bk y rb,dz--l2fp je*hz2igure from above)?

  11.41: For the figure showhzpx+kgy+25jok3,u kn, 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 resx;m1 e-(m lm 4pjmcr7oistance 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 plbn 8m0et4a--spc* i ixane 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 result of this field increase? b0a c-*et8 s4i-pimnx

  16.47: Two small loops of wire are3s2;rsdc -dbc located close to a wire with conventional current directed up the page. A scientist then moves the loops away from the current as shown. What is the ordb3 s2c;rs d-cientation 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 conductin- l6llnyxp5 nym92b*k g rails as seen in the figure. Throughout the region between the rails, there is a uniform magn5lbp6ml-2ln xyn9*y ketic 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 the currents through each resistor at the instant shown?

  08.50:. An infinitely long solenoid passes through the circuit as shown. Thedxoo:y8 b1u0a magnetic field of the sole oxyb1do:0 au8noid, 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 xzas+f( /8q; kcl,vpldecreasing 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 resi+slkl cq/pf;x ( ,av8zstance R in it and an ideal voltmeter connected to the corners through the center of the loop. What is the magnitude of the voltmeter’s reading?