94.20: A magnet is dropped thrci y 8lnofq e;k+;9u5eough a vertical copper pipe slightly larger than the magnin 5cek;eql 9 u8ofy+;et. 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 0azve 2uq--zx*i8qg sc;k-tr induced current in a conductor by a magnetic field couldq c-u zi2*;g0xav8k z-qts-r e be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is (h fvqvky z +vdkjo.m 6;5pi;9equivalent to which .j(o;v pzhkmi96fy vd vq; +5kone of the following?

  04.34: A square loop is placed in a uniform magnetic field perpesrd ty7lp)9+ :)cz+eyjx edsz)s7 xa0ndicular 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. I7d sy z7)jxta:cx+l )d)ep+s9e0srzyf 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 fielf // .dea njm( dghgunifk/8 k:r(:1ijd directed into the page. The wire experie:u18fh(iddgin k/ ekjfg( a.m /n:j/rnces an induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic fks ld;4z 0cy2q- 3u+lzf1biwjg f,qy.ield and experiences an induced charge separation as s- qfc3l12w f0z+;4ks b,j qzgldy i.yuhown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar mo 9. a6wabt76lid bfen5ving to the right on two conducting rails. To manbifa 7.9b6wdt6lea5 ke an induced current 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 induced s tk :lbst,r 2mq3snst98o)f+between the wire’s ends, thatstqto:ns9mtsr2 f,bs+38 ) lk 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/vypze-05 92i g 1 7nkh xp/lnage+r-eks 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 lpk9p/hg -z0x irng7 ya2 ke+l5-ev1ne ength?

  04.42: A solenoid is orit9 ;axl :j;- wqkyq,pqented end-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 neglig; jkqlp, wtq;q9a :y-xible 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 shf403ldachw +)jok1nf own in the diagram (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 needleo f)nh0 c+jwak4 1l3fd in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet is held ve p4uq0tniy5 :eli hc50ry 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 of conventional current through the resistor shown and what is the direction of the for pn h:005q ui5yct4ilece on the magnet because of the induced current?

  09.37: For the figure show2dj 3uvw2 7konx)ta5cn, the variable resistance in the circuit on the left is increased at a constant rate. What is the diren5kow2 tv3ujd x7 )c2action 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 ver;mwe5gjmtfe , e49pc 6y close to the opening of a solenoid as shown in the diagram c6e9me54e;f,wm tgpj. 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 represent?

  14.34: Two circular loops of resistive wire are placed next to kxi- vhbj;) up0;2p bseach 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 centers ;pb i ;k)2bvj-up0xh 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 resistaidnmjage(r 2nj;l9 / -nce 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, th-f uaw+ j3 h*j+wo( /pgsqt7vze variable resistance 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 wpp8mom 8hty(oa 2+* xgire 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 increases with time. Which one of the yx+2ph( o*pmo gt88 amfollowing effects best describes the result of this field increase?

  16.47: Two small loops y)+16(gadhjy v3ottpe / ln z8of wire are 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 orientation of the conventyo3 t8 nz1/ e v6)hyjaptd+(lgional current in each loop while this occurs?

  17.35: A metal bar is moving to the left acroagq7 iz nz /,d1;p bi291(ia1g xujldhss 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 conv 1iquz dpzn2h 9blja1g1i,(7ia/ ;gdxentional 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. The ma 5 .n/*fgojguk*gk/.ufjno5 g gnetic field 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 int2bl4d0sbri+ jr 0: g7g f8empho 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 ls+ 84bgm0p 70rhdir2:jebf gR 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?