94.20: A magnet is dropped through a vertical copper hx,hats(5 nvthe4*h;s m.f(fq 0q,v bpipe slightly larger than the magnet. Rela fh(sfv v 4;t.h0sa5xbhheq(, n,tm*qtive to the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced current inw,sr m a;d+lmu8z an9+011i1bftf)rp trc h9q a conductor by a magnetic field la1d+08p9qhfzmtrf, csnbram1 r 1 i) twu 9;+could be a restatement of

  11.25: The product (3 Teslas) × (2 n)na/wp dug:y48u,a,lg* h scmeters) × (4 meters/second) is equivalent to which one of the pl daacnn,u /*:8, syhgw)4ugfollowing?

  04.34: A square loop is placed in a uniform magnetic fielduhzs;8jr- : . ,t7jiskn1ptul 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 through t-ult r:1iz u 7hj;.s,jp8nskan angle of $90^{\circ}$ in 0.1 second what would be the average (RMS) induced EMF in the loop?

  97.32: A wire moves th/x;bhki j; j7-gqt o1zrough a magnetic field directed into the page. The wire experience;jqg/t1;-kz h bi oj7xs 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 experien rsbemf1 (qy*-1:hge9l 0 su3mqnru +nces an induced s ngl(f eq9q1*0m r3yubrh:su+-n m1echarge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to thliym5kn)e u.3 e right on two conducting rails. To make an induced currleunm5ky 3.i) ent i in the direction indicated, in what direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a m7 uc;lim5jy e m+0jt;6h 8sj5.u.zq ei)z nsbtagnetic field has a voltage induced between the wi+s60z85 je.)zm h; jnqcle5 ut;m7yjisi. utbre’s ends, 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 const dv5fyhuyn -e;i1 e l4;nee:k(ant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potential difference induced acrvef;e4hly:(d eeun51 - y;kn ioss the rod’s length?

  04.42: A solenoid is oriented end-on so thatt f2y+m4 mb4 k.m1yyjs 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 42 yym j1.ym+4skbm ft 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 (zmne1ao 5oe (8which are assumed to be close to each other), the o moenz18a(e5 resistance of the left-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 thcwg( 2d lmn).ge opening of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid at constant speed, what is the direction of conventional current through theg(g2. dnl )cwm 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* f)yfo33kse*ahd5oh 1 bz,1 amkm /qc;t xwd0 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 ce a) s 3xod*;aoy5qt3e,hzkm /dfcw*bh1f 0 km1nter 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 soleoah)1lr6.on nnoid 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 magnetion.6rlo1a)hn c pole does the “??” in the diagram represent?

  14.34: Two circular loops of resistive wire are placed nex .ahz dl/ah5cv(-2eivt 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 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 righ( hve 5la-cd2hiz/a v.t-hand loop (as viewed in the figure from above)?

  11.41: For the figure shown, the variable resistance of the outerhn+; doc fq:r4k u;3ir5:ret b 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 kokpu3698iqz8bh ns q4l2ejf-s a1 2vthe 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 sit-p5cuyix 8 (.ag8gq ows in a plane perpendicular to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strength steadily increases8q 5g -ui(gw .cpaxo8y 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 c .8ge hpo:jn:durrent directed up the page. A scientist then moves the loops away from the current as shown. p8ojhn : g:de.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 frictionless conductiz+i.4be86kafmy yp u1ng rails as seen in the figure. Throughout the region between the rails, there is a uniform magnetic field directed into the plane of tibauykf8p6e . +14ymzhe 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 lbl* a c,7vu0beong solenoid passes through the circuit as shown. The magnetic field of the, l0a7vbe *ubc 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 directed into the plan+:q 0,jkw v)yzd mdm;pe 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 idv mmk,;zjyqdpw+:0)d eal voltmeter connected to the corners through the center of the loop. What is the magnitude of the voltmeter’s reading?