94.20: A magnet is dropped through a vertical copper pipe slightly 7;akg-ue;imz larger than the magnet. Relative to the speed it would fall in air,a;zekg; -u 7im the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced current iyi9ydtj*nm430 z)6-owmq jgy n a conductor by a magnet gyio0 zjtdwymn9)4jm *3q-y 6ic field could be a restatement of

  11.25: The product (3 T,castf g3u.k9 :.rjwheslas) × (2 meters) × (4 meters/second) is equivalent to hfwg9 ct.uar 3js,k: .which one of the following?

  04.34: A square loop is placedi6l r- eur clze9jh(rn f:j :a*gj0l68 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 g(-nerjlur:j j0zihll66e :f8a c*9 ris 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 throz;)v -u 46c /sk1xdarf, utmfpugh a magnetic field directed into the page. The wire experiences an induced charge separation as shown. Which way is thmad fpctsru ;-f)z,xv k164/ue wire moving?

  00.20: A wire moves with a velocity v through a magneakzkjxne(-l+ch -4 q5q*zx w+tic field and experiences an induced charge separation as s4j k+zk+-h qqnx 5zwae(x-*cl hown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the , vqi0p-1gz4gczo rat-6hw1mright on two conducting rails. To make an induced current i in the direction indicated, in what direction would the magnetir z ,cgva0w4tzm-1p hiogq-16 c field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field has a voltage inducedno3 w.na ih.of9)a t/b between the wire’s ends, that volbnf) /.a3aio.on 9htwtage 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 traveling throu t3u;du,l1mhe9mt/ /d mfqhv,e)jc v8gh a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are alldh3, d8hc) mq/ jv;/tm91 ufvetm,el u mutually perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its ozka 2e/:c5blo pening 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 aelcob/ :2zk5bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (which are assumed to be close teiy,0.a5esf1w) wid)dg rs g3 o 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 refw)gg d). 3s awi,y51 ied0esrsponse to this change?

  08.29: A strong bar magnet is held very close to the opening of a solenoid as46it*hvfsk7kd)wr0q ,n kz mc .8k 9fv shown in the diagram. As the magnet is moved away from the solenoid at conf 0qm.,kr94hs*nzvc)7k 6vf kkdtwi 8stant 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 resistancm a/p1, da:7nfp 7ciot-b: hexe 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 center of the left-hand circuit and in what direction is the conventional current through the resistor in the right-hand circuit?,atib me/1phfxc7pd:: 7oa -n

  10.39: A strong bar magnet i90ikrd1hr h1m5zn1 uos held very close to the opening of a solenoid as shown in the diagrz norr01 md51k1u ih9ham. 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 each other as zs flfd 13m+3wactle7) o7*uw 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 poifd owfa*37sm)uelt13 c w7zl+nt 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 vw(/l(j* 7sakl+( :x zcrx6cz j7bt ;bymo vy0of 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 varm3ctl- t -k2y+*pcixriable 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, conduc4aigwse8; eb4qn qd1ygo )* 3nting 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 one of the following effects best describes the result of t14sa 8wn o) qig;*gyd4bq een3his field increase?

  16.47: Two small loops of wire are located close to a wire with conventiiz6/cwtzj gu*8+k( omonal current directed up the page. A scientist then moves the loops away from the current as shown. What is the orientation of the conventionu *tgo(i8j/ m 6zck+wzal current in each loop while this occurs?

  17.35: A metal bar is moving to th*;1vt /f4uf7t8y xz y6ej-g 5ybblcdwe left across a set of frictionless conducting rails as seen in the figure. Throughout the region between the rails, there is a u1lexcu*y8 7wfj/y6-4by vbf t gd 5;ztniform 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 lo qjq7zuxag ql+6t*0qoudos 4kna+( .5ng solenoid passes through the circuit as shown. The magnetic field of the *ojqu6k5+q40+sl.gdo7naz a xquq( tsolenoid, 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 d l*gaef9*+z sbirected into 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 R in it and an ideal voltmeter connected to *z seagl* b+f9the corners through the center of the loop. What is the magnitude of the voltmeter’s reading?