94.20: A magnet is dropp9pbpv:0; t4 ob-ht7lq3 ywbry ed through a vertical copper pipe slightly larger than the magnet. Relative to the speeb0;43tv o9bp tyy bqrl-7h p:wd it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the kiz ki/qn*(u /wf0ht .direction of an induced current in a conductor by a magnetic field could bzu *n kqti/ik(hf/w.0e a restatement of

  11.25: The product (3 Tesla.c9a:tkyhwqmu:ixggwvm oo7 / 8u..+s) × (2 meters) × (4 meters/second) is equivalent to u va8w.owm:7mh.qk.uy:xc9t/o g+giwhich one of the following?

  04.34: A square loop is plhvqoz-q6, dow0e8s4 aaced 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 ro wsq84hvazo 0 ,od6-qetated 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 pagehkcs9b 112q/ u7x4 bmtix/r me.y*rjp. The wire experiences an induced 1xky9crr ixt 1j ue./b2mbhqp/4 *m7s charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velociteh2cn 2 h670bg r(hccby v through a magnetic field and experiences an induced charge separation as shown. What is the direction of the magnetic field (2b0hen27bc6hhgrc c ?

  05.33: The figure below shows a bar moving to the right on two conh l4he+ggm9f eb -m0p7-uxt k7ducting rails. To make an induced current i in the direction indicated, in what direction would the magnetic field be in the area contained within the conductifhkp-9m07elegum 4hbt7 x +g-ng rails?

  00.10: When a wire moving through a magnetic field has a volta8l4i oqq. 3c2zdppvy+ge induced between the wire’s qiq38yo .+lz24pc vd pends, 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 t85ta(p ixsu* oraveling through a uniform magnetic 8sxu 5ai*p ot(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 length?

  04.42: A solenoid is oriente xej2z;7c2voatyv8 5wd end-on so that its opening is perpendicular to the circuit containing the two light bulbs as drawn in figure C1. For 7jeyacvzt v2 582wox;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 bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (whicn7e sk;ab-*gor2 1 lfsh are assumed to be close to each other), the resistance of the left-hand circuit is slowly increa na7orl- 1;efbg*s 2kssed. 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 clz ky . vv4dbtdy5(/*iyose to the opening of a solenoid as shown in the diagram. As *v k vidtbzdy (5y.4y/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 thezxyu v(4d)*j q 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 indq4 xj)v(z*u y 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 ofsnku ,2 auq xxaz-/29o a solenoid 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 “??” in the diagram reprk-z aa o x22u9nuqxs/,esent?

  14.34: Two circular loops of resistive wire are placed next to each other a xr6aayo*sogn .(;z3yzp*wh3s 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 center of the left-hand loop) and what is the orientation of t*;sayn rpyzwgxz(o ao h363 *.he conventional current in the right-hand loop (as viewed in the figure from above)?

  11.41: For the figure shown, the variablvv4tlrp v y37dhn+y,; e 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 ws925th)wb6t*z dzzq e2g. i *yyw*nlvariable 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, condue4bh)2 b5 lek.c7jstdcting wire loop sits in a plane perpendicular to a spatially uniform magnetic field po.bhsle45)ecjk2 b7 d tinting 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 this field increase?

  16.47: Two small loops of wire are located close to a wire with conventional n1.ph,h y86son zuw x12v1 czncurrent directed up the page. A scientist then m8uv n6psn.zx11c1hyh onw, 2zoves 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 o)kvru27a8at81*fs 2o t x eilwf frictionless conducting rails as seen in the figure. Throughout the region between the rails, there is a uniform mar ea2tlav)*i2otkw 8u187sxfgnetic 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 zb-d93-avi kcpasses through the circuit as shown. The magnetic field of bcdi k3z-9-vathe 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 dirjicuzn6n+y oz 5,;m1o ected 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 the corners through the center of the loop. What is the magnitude of the voltmeter’s reading? +z1oi6 znj,o5 n; cmuy