94.20: A magnet is dropped through a vertical coppje0q7)9 0qc y0x7msipcu 5csaer pipe slightly larger than the magnet. Relative to t5 0ej07c9 07acqsm xipquy)sche speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induce. jf9bmg7x.ke)sca4 bd current in a conductor by a magnetic f9xakb ).csj47. b efmgield could be a restatement of

  11.25: The product (3 Teslas) × ( /m/eebtl w,7ymia83/u sl g+ry-j9dl2 meters) × (4 meters/second) is equivalent to which one8gm/i dr la3y sjl7t/e/uyw- m9e+l,b of the following?

  04.34: A square loop isymd-8k / +gttlph-pm7 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 throhk ly/ p7+mt--dtpgm8ugh 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 t/c s5vy,:y*f8ubij p through a magnetic field directed into the page. The wire experiences an induced charge separati8,py: s5/ fbjcti vy*uon as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magneticgez0u8oushapu;.,9g r/pr(mry 9 s f1 field and experiences an induced charge separation as shown. What is the direction of the magnetic fielyrumz, rs9.0 9(uga/e fu1op;g8phrs d?

  05.33: The figure below shows a bar moving to the right on two condj)jewrcm 9, p-7 8xf1ryip bhhv.a;8zucting rails. To make an induced current i in the direcr 7fc9 jz,)phv8;r1m- bwa p.eij yh8xtion indicated, in what direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving v:qcls:0nx *c6i: 1tn .ysyvlthrough a magnetic field has a voltage induced between the wire’s endsyi:nx*s: ntc1vly:svc.0 6 ql, that 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/s traveling throughjgjx,by8 w02x a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic fiej0, g8jybxw x2ld 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 opening is perpendicynw/zmf+;-ek ular 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 fi+z -wk;f/nm yeeld 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 diagram (which are assumed to be close to esx 5-9 yt6nhrpach other), the resistance of the 69 -tn5r xhpysleft-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 63 vo bscmfx+/5rq ws2of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid at constant 2bqs3+5 x/sov6wfmc rspeed, 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 resir27 bj ddw24xrxs5 n7cstance 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 td 2b2 57r4nds xjcrwx7he 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 sole bq/wd5 vbawuq1jp 59;jcv/q8noid 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 force on the bar magnet because of the induced current in the solenoid and which magnetic pole does the “??v / cwjb8v;/1abq9dpjquw q55” in the diagram represent?

  14.34: Two circular loops of r0v(h9 cypuuyyp:2 c8uesistive wire are placed next to each other as in the figure. The circular loop on the left is connected to a constanuu:82yu9 yvp ypchc(0t 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 u+,yq2 koo.:3l *hr-fbpptls 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 resists68 ;7a z ugk*ave) *5napepgvance 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 plane perpendiculayflm7i5*rwa eu:3-bbkq 4 bi 9r to a spatially uniform magnetic field pointing into the plane of rbfaieqy* 4iwb: 59k 3-u7lbm 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?

  16.47: Two small loops of wire are lo2vfu0kmkk:c7t ) 2 dxvcated close to a wire with conventional currentkukt)d c vmk0xvf2 :27 directed up the page. A scientist then moves 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 tmo je8qp0dh8 3e ):ipset 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 conventional current in the resistors and the relation between the magnitude of the currentdp:jp 8oei 3he qt)m08s through each resistor at the instant shown?

  08.50:. An infinitely long solenoid pas8o8 y+g n4hmtm4ih zn3ses through the circuit as shown. The magnetic field of the solenoid, dirni8o +m434zythn8m g hected 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 planur0 m /s,ewkyvp:v:w8l+7utwe 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 the corners through the cep vs,/ ru87tyvwweu:k0ml w:+nter of the loop. What is the magnitude of the voltmeter’s reading?