94.20: A magnet is d4iou8ivbq)u v.1;ln dropped through a vertical copper pipe slightly larger than the magnet. Relative to lnb o;iduu.vv1q i)84 the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the d5xf-rw, w ie)oirection of an induced current in a conductor by a magneor)xw- fwi ,5etic field could be a restatement of

  11.25: The product (3 Tks f.k9klj-luv3 6m+ qeslas) × (2 meters) × (4 meters/second) is equivalent to which one of the followi skv9km+l3 ulfk6-jq .ng?

  04.34: A square loop is+ceg o84h (mfoslm6oyxriy5; -(t77nc-k p y e placed in a uniform magnetic 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 rotated m;6g ec cr +(ho(oy4p-5sey7lxtyion8 7 m-kfthrough 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 intod+yc8p:gwfkt*9j:tv z +zk z7 the page. The wire experiences an induced charge sg f:7+jzk 9dz8wtyp+ctkv* :zeparation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v througf*x 7)0 1wuqsi2wyjhnh a magnetic field and experiences an induced charge separation as shown. What is the direction of the magnetw1x 2 0qu yjnsifh7w)*ic field?

  05.33: The figure below shows a bar moving to the ed h.x ,1ds7pg;l+rpzright 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 with. zxg spe1+pd,dh l;r7in the conducting rails?

  00.10: When a wire moving through a magnetic field has a voltugfnuc.qm)(8 age induced between the wire’s ends, that voltage iq)u c 8fg(.nmus
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 coppp 75 hdl3.c2ipv1b z-z1ggcdoer rod has constant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. o gppd cb7 z12idvh.3c5-zg l1The 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-p 7j 4(ncwyig4on 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 th (7gjn4ywpci4e 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 dic9zhdd qm*20 zagram (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 in response to thid2 qm9c d0zz*hs change?

  08.29: A strong bar magnet is held very close to the opening of a solenoid as pa/vr c9 z 9r7bhke 0+(j ootfo(ysj75shown in the diagram. As the magnet is moved away from the solenoid at constant speed, what is the direction of conventional current through thoa 09yz prt7s9kvo(b5fhre/ jj(c+o 7 e 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 circuit on 2bt2:gvowx5 qi sxl/j/c; se:the left is increased at a constant rate. What is the direction of the magnetic field at the point P at the center of the left-hand circuit and in what direction is the conventional curx isj5 /gwbscqv;et:x l:2/2o rent 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 j7gryjdx )fvxbd*)+4 *; oiezshown 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 fordbye * 4i7 ozfd)xx;+j)v*jrgce 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 q-hzn 7v.mi2 bg4pfgo,u.rp63 3mcv-ru4fmy of resistive wire are placed next to each other as in the figure. The circular looqc3u-pzv7r,h -my f g 2rig3uof.mn 6vbpm4. 4p 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 figure from above)?

  11.41: For the figure shown, the varjt8p-d;jmxost) k zz.+hp. /kiable 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 varg4)i9bd i9z8;l3ss t whf l9aaiable 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, cont 85k-t3uoprdp szbg x9j0))xducting wire 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 o) rozx3d50)xg bu8- tst j9ppkne of the following effects best describes the result of this field increase?

  16.47: Two small loops of (yt n0ht6r4f ywire 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 f6t 4nt(y hr0yorientation of the conventional current in each loop while this occurs?

  17.35: A metal bar is moving to ( cv wp/5vtxnicye 2q/.d*.dqthe left across a set of frictionless conducting rails as seen in thec i(.*nev.t qwdpd /x5ycq 2v/ 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 the currents through each resistor at the instant shown?

  08.50:. An infinitely long solenoid passes through the cfg 3abvma)6i/ ircuit as shown. The magnetic fieldbfg via)m63/a 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 into the plane of the page is decrervu.5soott8ns4l: .qyy z5gbc k;)9tasing in time. A constant emf ξ is produced for the square loop enclosing the field in the figure. The squactoq sk:nzyt;tyo9v r ..8u5s bg)l5 4re 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 reading?