94.20: A magnet is droppedaeer20bt f- d( through a vertical copper pipe slightly larger than the magnet. Relative to the spet-bdeer2( a0f ed 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 co p e svc(.9yh9b,ne:mbnductor by a magnb9ne(mp c9sb hve:,. yetic field could be a restatement of

  11.25: The product (3 Teslas) × (2 meterjjcp74/vxk /p s) × (4 meters/second) is equivalent to whp/ kpx7j/c 4jvich one of the following?

  04.34: A square loop isi0/ g,r ;*t/1h,qm 0cxgxgfr vhm*mq p placed in a uniform magnetic field perpendicular to the plane of 0vqqxr 0/,g1*pimf,hrm;x/ hg tcmg*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 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 direc5uh)4+ojs8e qf ujy9n ted into the page. The wire experiences an induced charge separation as shown. Which way is tjhej89s+u ) 5uqn4 oyfhe wire moving?

  00.20: A wire moves with a velog1dr*tir3jwou*9 r8 ncity v through a magnetic field and experiences an induced charge separatijr**g3 1tiudrnw8 or9on as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right o0gk * b)bqcfcts q,,)ln two conducting rails. To make an induced current i in the direction indicated, in what direction would the magnetic*b,bc t)k0gc s qq)lf, field be in the area contained within the conducting rails?

  00.10: When a wire moving through a mg s2f4x5*mitj h3vt2nj dh :9qagnetic field has a voltage induced between the wire’s ends, that voltagex22*h59d js3qt4h tg fiv nm:j 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.wk-:,cbv tg1v d/k2.:niu fgq30 m/s traveling through a unifk:./b wdcg:kn 1ifu g2v -tv,qorm 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 length?

  04.42: A solenoid is oriented end-on so that its o4gg/x(rn yaiopry7)p *k y*e3pening 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 fay4pg3ypnrixgor*y( ) / e7*krom brightest to dimmest.

  07.34 For the solenoids shown in the diagram (which are assumed to be close pknv(6zu4t1 xto each other), the resistance of the leftzptkn6v 1u4( x-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 held very close to the opening ofc-2bap+5xthb8p c .vy a solenoid 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 dirb-5yb ahptvcx.2p+c 8ection of the force on the magnet because of the induced current?

  09.37: For the figure shown, the varixo)x1x 8bznu1:b uz3mable resistance in the circuit on the left is increased at a constant rate. What is the direction of the magnetic field at the point P at the ceu :m3)8ob1z1 bnxxx zunter 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 i/mi,wv1 f7 twqs 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 forc/7qi fwt,w1vme on the 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 z+g( ry,t fl6l-(qxmg of resistive wire are placed next to each other as in the figure. The circular loop on the left is connected to a constanq-xgf6z ymtlrl,+g(( t 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 shown, the variable resistance of the outer cnsycl0fcql -ts2c +9+ ircuit $R_{inner}$ 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 theio fz/n 1/mw9t 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 plane perpen4oem: id3/k;3wc kbk0beh(vcdicular 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 besve4dc0 o/ k ;eikmwbh(3bck3:t describes the result of this field increase?

  16.47: Two small loops of wire are located close to a wire with c.+ ls3 mpgzz0bonventional current directed up the page. A scientist then move zgpb3l+m .0zss 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 a set of fricti s6jgfshj2x 42onless 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 thsf h2jjg 64s2xe resistors and the relation between the magnitude of the currents through each resistor at the instant shown?

  08.50:. An infinitely longnpae z1 suaw/fr+s 5yy)) -+gx solenoid passes through the circuit as shown. The magnetic field of the solenoid, directed into the wpeau y 5)z/ a+r)gxssy 1+-nf
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 timek, mks2v r6-0daji 7jy. 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 center of the loop. What is the magnitude of the voltmeter’s iy2s,ma6dkjjk0 - 7rv reading?