94.20: A magnet is dhub8rd( */d oyaynj 6d*oo.6 zropped through a vertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magnet in the pipe falls:h udo.6z8/6bjda* rdnyo*(yo

  01.30: Lenz's law concerning the direction of an induced current in a conduct.l 7;2ne:jq* ,nba bh d:nxezuor by a magnetic field could be a resta*e2nqxln jh nub.,;d bz a::7etement of

  11.25: The product (3 Teslas) × (2 meters) × (4 metespx 1x yww925 f6r w,z,fvv1ikrs/second) is equivalent to which one of 1wpvi6 1f r ,z9yx,5fwsk2vxw the following?

  04.34: A square loop is plyph.+d .:x -vjyy 0:zsaomn8i aced 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 rotated through an angle of yyh+ :pizxsvd:.0-amj n o8 .y$90^{\circ}$ 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. The3wk ge v/g7b u7tx77jd8rse(d wire experiences an induced charge seejgwd7bevu/k 7g3d 8(x7 ts 7rparation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magvkedy 8d* wk+uuy:g/2netic field and experiences an induced charge separation as vy2w8g*dkkyde uu/: +shown. What is the direction of the magnetic field?

  05.33: The figure below3+ub ,x0 . phpccsta;v shows a bar moving to the right on two conducting rails. To make an induced current i in the direction indicated, in what direction would the magnetic field be incp+pu., x thb0v a;3sc the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field has a voltage indulpic 22 tv gd-* 5he31ftv)oszced between the w t2oivzp shv*de13l-fgc)2 t5 ire’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 constant velocit0,sqdk; q(yw2)y- e ypaqy -fqy 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually f0aq2(y;q,wqyysek q p)y-d -perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its openiw85uvp +-g :9 hzh i-ouw5rqxvng is perpendicular to the circuit cont -rw-q:5v+ho9 g px5h8wiuzuvaining 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 dimmest.

  07.34 For the solenoids shown in the dnruzxaw6rp7e ikx1-0xh q -k+ jdv58 0iagram (which are assumed to be close to each other), the resistance of the left-hand circuit is slowly increased.e -i 8rx5rdjnzkv7hpkw1+a- 0ux06x q 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 the opening of a solenoid29c; nxx unv9kzx.v6b as shown in the diagram. As the magnet isbx n c6n2v;.vz9xxk9u 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 circuit on 9tc 5:a xd pj96o-;rzx 6xaxcethe left is increased at a constant rate. What is the direction ozcex rtpa- x jcx6a959o6dx: ;f 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 hel z, )* pblv7t5fg(snahd very close to the 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 dire7h()5,* v szb tpafnglcted 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 wire are lurbt q2(sx0/ e4ha7b 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 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 curren4x slb 7ut2 r0(be/ahqt in the right-hand loop (as viewed in the figure from above)?

  11.41: For the figure shown, the variable resistancgld2k1f.tqsi(h 1c(w j* k/h we 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 6kp.pr h y0 *bzuoy6p(6no3r xshown, the variable 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, conducting wire loo jc /x1xjogp;:1 ib:jsp sits in a plane 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 fol1gc/jxi:s: o1 jxpb j;lowing effects best describes the result of this field increase?

  16.47: Two small loop, s1kk(h dkug5s 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 each loop whidu( g kh,s15kkle this occurs?

  17.35: A metal bar is moving to the left ac4bd 176gk k hfj 8xlbpfse/39ei;qs4aross a set of frictionless 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 e/x8 s;epa4 js 31d 4eikhq9f67kb fbglach resistor at the instant shown?

  08.50:. An infinitely long solenoid passes through the ciintixjy 9;11 srcuit as shown. The magnetic field of the solenoid, dire1t1x;is yj9 incted 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 pla5cf mnb;;(k qlb0 9 o)mcg 1a9uvb1yzt46hu btne 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 loopbhtm 1muat 6qnobkgu c(1y0 lc5bf;)4z;9v b9 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?