94.20: A magnet is dropped through a vertical copper pipe slightlya ,.tx4ip c)qe larger than the magnet. Relative to the speed it would fall in air, the magnatqei ,4pc .)xet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced current in a54 4 jhgpdt;k:qoj1cr conductor by ht5 1: 4pdjrkq4og;cja magnetic field could be a restatement of

  11.25: The product (3 Teslas) × (2n pg1 z2q,btp2 meters) × (4 meters/second) is equivalent to wqg22,nz 1ptpbhich one of the following?

  04.34: A square loop is placed in a uniforjp gukmk6.xxrjgtq(0f ( g.8 /m magnetic field perpendicular to the plane of the loop as shown. The loop is 0.5 meters on a side and the magneti(t0jgm g6rpfxjk x./. g(kqu8 c field B has a strength of 2 T. If the 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 directo lgb9v+o:8yfed into the page. The wire experien o 8:ofbylvg9+ces an induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and experiences w1)io8 :hmt e+y iayt5an induced charge semioywhye)a :+ t185itparation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to * w8wy4gdivh (the right 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 contagy8 i (w*w4dhvined within the conducting rails?

  00.10: When a wire moving through a magnetic field has a voltage induced betweev8egrd*z l 66ln the wire’s endvl gz8*el66dr s, 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 long3jo2 z n6lk qwmj+o0gyq,h1 2h copper rod has constant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. Thhyj+l z2hwj3k qg2m0no6o1q, e 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-on so that itcetbvunpqf)b n a85 9;-dl:5 fs opening is perpendicular to the circuit containing the two light bulbs as drawn in figure C1. -t5fda)8n9f :;bnvp5ucelbq 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 bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (which are assumed to be close t.bmm7e hk)j3 yo each other), the resistance of the left-hand circuit is slowly increased. In which direction does thejmyk3)b7mh . e galvanometer needle in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet is held verm; es:o s8u8,8uhx mmwy close to the opening of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid at constant speed, what;u eu :w os,8h88smmxm 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 circuit o:q*nl ;xedfmn1-n- z (e7vg) )oxlutfn 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 resn-ex-7 n:)exgd (lvtff nlu;) m*1oqz istor in the right-hand circuit?

  10.39: A strong bar magnet is held very close to the 20 kduxkd4bk9opening of 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 magne90bdd ukxk24k t because of the induced current in the solenoid and which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of66rf s*e3uiqv:ev 7zn resistive 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. f3zr vs* :viq66neeu 7The 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 variab5xl.zjp7tsxp8t-sp6z - p /uoe-ox6d le 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 resistancupf2r.jj6z-hpjlwk.dx /8tj /zu5 5i e 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 wi ozb+d5 (-o3riv2yekyx7u fo .re loop sits in a plane perpendicular to a spatially uniform magiuvzof+oy2e kbd .oy3-(7x 5rnetic 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 this field increase?

  16.47: Two small loopmh/uzk +cjo z(i) r*8ys of wire 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 orientation of the conventional current in irjz y8hm)z+c o(/ uk*each loop while this occurs?

  17.35: A metal bar is moving to the left across a set of frictionlb7qe9pn y2*oxess 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 currents through each resistor aq*9ybe 2n7pxot the instant shown?

  08.50:. An infinitely long solenoid passes thrbde- *rlcg5i7ta w 06i*m+ m;ejmbhb:ough the circuit as shown. The magnetic field of the solenoid, dia6e7;bgim e i+w br*mt0 cb*:hlm5 -djrected 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 int h kbcy+rj eh(l 5v1q59wu 8,i.yfvz3.0wh xiko the plane of the page is decreasing in time. A constant emf ξ is produced for the square loop enclosing tkf b 0wvh8er.ikx,y5z 153 v.hh u9q(cwjyil+he 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?