94.20: A magnet is dropped through a vertical crcoqy7*r bhqh d,ch- y8s 9z)+opper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magnet in thhh)7c,sohb ry q-+8 qrc d9z*ye pipe falls:

  01.30: Lenz's law concerning the direction of an induced current in a co 7hiiy,wg. -8q ,kw(ziyy cru5nductor by a magnetic fi,(w ikwryqy7h-c8 ug,iz.5i yeld could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is equivf1 me jvibw,xe,zqv9jw 8 2--kalent to which ov,j9ww- z b1vx8e,-fk qimje2 ne of the following?

  04.34: A square loop is placed in a uniform magnetic field perpendicular to 5.qend4ox vkko-ux/*0 lrw y;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 nrkq4xkw - xu * ;05vde.o/lyothe 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 directed into the page. Tipkbsgas79 uk68ci3t w7 +gkj 1w:2 wbhe wire experiences an induced charge separation as shown. Which way is the wire mousbs8+ k:cb1wkaw i7t g3j 6i7 p2k9gwving?

  00.20: A wire moves with a velocity v through a magnetic field and experienu +en59)pa qffces an induced charge separation as shown. Whatff+ qnu9a5)ep is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on two co ny n4h.(7gok3 lvlzm*nducting rails. To make an induced current i in the direction indicated, in what direction would the mavo*n7g zn(m4kl3 y .hlgnetic field be in the area contained within the conducting rails?

  00.10: When a wire movzp.:r r (y-xx2:dh(sp s0mqw ding through a magnetic field has a voltage induced between the wire’s ends, that voltage is : r(wm(r0q2zdhp-.sx:sx p yd
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 c.ony yt/x(ua :m;9lsr onstant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magneticnxa9y:ltm / or. s(u;y field are all mutually perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on l r6k yx*+o/5e +7.8bgozv*nfm bxqyq 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 the page, decreases /5 l7bq.*nvgyy++xe6r bqmk*o8 zfo xuniformly 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 sh6kt 5gv y:px:cown 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 needle in the right-hand circuit move in c ytxpkv65g: :response to this change?

  08.29: A strong bar magnet is held very close to the opening ola:;lo 8jeq6hcwr/1of a solenoid as shown in the diagramc:o1/8r lwl6e o;aqh j. 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 force on the magnet because of the induced current?

  09.37: For the figure shown, the variable resistance in the cilc4468+ndbl nv,ru46inxk94i wj gks rcuit 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 lenci k g8rs+nb4i9ulj4wl ,n64v4 x6kdft-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 openi;,l3tvg/6wqtl ) iolqng of a solenoid as sholt igvtl 3;6/)q,o wqlwn 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 “??” in the diagram represent?

  14.34: Two circular loops of resistive( vx7w8gwno p9 wire are placed next to each 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 7oxw9g8vw (p ntime. 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, xtyxqi6c* ylx )(3r c0mnc)*othe variable 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 variable resistance of the innerchz-f/+ sm 7fp2i 3qd m9z(bcawi/sye*ircuit $R_{inner}$ 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 tfd8 5v.l n/s(cpdkn, 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 r/tk (fc.s5,l8nvnddpesult of this field increase?

  16.47: Two small loo ozk3*v 8l9bnpe0tq8wdlt n7p(u l3k/ps of wire are located close to a wire with conventional current directed up the8bzkdqe pt73on(0k *vw38 /p tulnll9 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 set of fricl53f 5mg ;faet 5jpcj7tionless conducting rails as seen in the figure. Throughout the region between the rails, there is a uniform magnetic field directed into ejgmpt75jff3 c5a;l5 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 circuitv5baia3y j-n5f2 a5q qb d.7cx as shown. The magnetic field of the solenoid, x5i v2 a5d-3aj f.abqcnq7y5b 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 di9fc cwzy v0t; a/1(sworected 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 vovszty f(o0;1 / ca9wwcltmeter connected to the corners through the center of the loop. What is the magnitude of the voltmeter’s reading?