94.20: A magnet is dropped through a vertical copper o 85z phj+zzh-x f 1wfv: rwg(sp0* kgdw:r06cpipe slightly larger than the magnet. Relative tc h *+8(0gzpd:roj:k0vhg-wx5w z1srfpz f6wo the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerni v8tdk q:4f(,d0qsa rvng the direction of an induced current in a conductor by a magnetic field could be a restatema, :qv8 (4dv0d ksrtfqent of

  11.25: The product (3 Teslas) ×0 rccmo +gdl0rn san) s 2pr6423h1ict (2 meters) × (4 meters/second) is equivalent to which one 3 0ca sgti c+21m lh4r2s)oc6rnd0 pnrof the following?

  04.34: A square loop is placed in a uniform magnetic field perpendicular to thk b;v:v/2p ,qjdal zb/e plane of the loop as shown. The loop is 0.5 meters on a side anda:bbpz/jq d,k ;v2/ lv the magnetic 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 /uzg9eju4 h 5 :awl1 b0jrv9 e4xkws(rv9zr.ndirected into the page. The wire experiences an induced charge separation as shown. Which way is the wire msu4l1 a .94wk9ehzre z/n9j5rw 0vg(:vju rxboving?

  00.20: A wire moves with a velocity v through a magneticq, x4v md1u *y*3lgux hje pcmw,bp*)/ field and experiences an induced charge separation as shown. W,x u1m3l *cp ,m*4puqb/ewh*yjvd)xg hat is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on two co f8 uccz16; ;k+( o.jyf 3svcowqrjx4onducting rails. To make an induced current i in the direction indicated, in what direction would the magnetic field be in the area contained wc(41f o +v.zkoj q; 3xof8 cj6ysruwc;ithin the conducting rails?

  00.10: When a wire movinj8q6 +jillzl/otd6 x)g through a magnetic field has a voltage induced between the wire’s eniltj 6l+xq )/dlz8 6ojds, 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 g6(br ++tnfiu cbe55 2(wlzerconstant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all m6g5z(li5rn2wbe(b + efcr+t u utually perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its opening isx4/p ..yz /4vz;7c)hdjlxd o0w niovx 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 uniformly in time at the same rate for each circuit. Rank the circuits for the brightness of the bulb labeled R1 from brightest to dimmestyxpdi0.od. 4vv/z)4xl jn xzh7o/w;c .

  07.34 For the solenoids shown in the diagram (which are assumed to be b-a4spw 2e:aex e ke66close 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 x: ae2wek6bea e 64p-sin response to this change?

  08.29: A strong bar magnetpnro6oj 00a9kbm: jplwn/ 3y tu+7 :wa is held very 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 is the direction of conventional current through the resistor shown and what is the dire/0j +0loow: pra j knuw p3b6yna7t:m9ction of the force on the magnet because of the induced current?

  09.37: For the figure shown, the variable resistance in the cc q+kgot ,5b-5vm fxob(5r3mo ircuit on the left is increased t-b f+xgm3b rov5k,ocq(5 m5o 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 resistor in the right-hand circuit?

  10.39: A strong bar magnet is held very close to the kxf+k51w. nra opening 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 direckw k.+nxa1r5 ftion 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 resistilc(kgdl y0 cq4,2 4vs-lcvr/sve 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 witdgsv(lcvq-02lscrc/ ,4 lyk4 h 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 y-oc0 +ano1b2zkhdr*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 innced 5*t9a-ol(m rwm*7vs4v rhercircuit $R_{inner}$ 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 i)mrnuwfdlybl0c( +i(ka z5g51v57 o sits in a plane perpendicular to a spatially uniform magnetic field pointing into the lkgan05 +li(y (iw 5mz71v fb)odru c5plane 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 with1:p x b eg;kpthaq/5.l conventional current directed up the page. A scientist then moves the loops away from the current as shown. What is the orientation of the conventit. gl qehp/:51xab kp;onal current in each loop while this occurs?

  17.35: A metal bar is moving to the left acro,7s rv-bco hu7ss a set of frictionless conducting rails as seen in the figure. Throughout the regiov cu-,bhros77 n 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 at the instant shown?

  08.50:. An infinitely long soleno .sm);xb)0+t chl u;u0wxt evvc(q)mr id passes through the circuit as shown. The magnetic field of the solc ;)))t(+s0q u c0vvbu;wl xmrthem.xenoid, 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 plane of the page idq im4g1a*gxs9-w *bvs decreasing in time. A constant emf ξ is produced for the square loop enclosing the field in the figure. The square loop h gi*xa1b-*d9qs4v gwm as 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?