94.20: A magnet is dropia (nx xp9f+j2ped through a vertical copper pipe slightly larger than the magnet. Relati+pi2x j9n(a xfve 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 ggj 29 5fac7mu;l(nqqcurrent in a conductor by a magnetic field could be a restatmg(njqgul2fa7q;c 95 ement of

  11.25: The product (3 Teslas) × (,yxf)h snercj270v l32 meters) × (4 meters/second) is equivalent to 7 e2n,rjfshy3clvx 0)which one of the following?

  04.34: A square loop is placed in a uniform magnetic field ji 1 j +zec; 2y9sqe2g0o+odjzperpendicular 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 thj s1d9cjiqzze 2jye 0g;o2 ++orough 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 d p7ow2ch;l dd7irected into the page. The wire experiences an induced charge separation as shown. Which way is the wire mop;d d72c 7olwhving?

  00.20: A wire moves with a veloci09g7l kzp3js 3x0 crxlty v through a magnetic field and experiences an induced charge separation as shown. What is the direction of the magnetic fiels0c xz03xp3 kljgr l97d?

  05.33: The figure below shows a bar moving to the right on two conduck)d40 mf jodhe,n01syakj 5l9ting rails. To make an induced current i in the direction indicated, nd 1054d0fk ha)9eykms jj lo,in what direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through dz04*cgwkx (ia magnetic field has a voltage induced between gxc* kwdz04 (ithe wire’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 velocity 0.30 m;hb c(-w5gclba,sex.,g7 v7c we.xpm/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpeb ;,gxlmv 57c7w(esx-.ceab.g c,hpw ndicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its opening iiku1ms5/z5gfe 8t 6y7o tp6wy s 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 brigiu 1t6se75t pmyo /y8 wz6fgk5htness of the bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (which are a;b87 f 3gp*1 (eibp(zqthussi ssumed to be close to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galvanometeriu 3sz7(fqb *s;t8g (bh1ippe needle in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet is held very close to the openinz6 cn up xhdy/f2;aafg -w-i5x/8qz;kg of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid at cy6u;k5 haxcqf;z/p-f /gi8n x -2zwadonstant 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, th yr 0/ogt+r u/jhd;c7si2 x2hte variable resistance in 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 center of the left-hand circuit and in what direction is the conventional current through r0xtgyi;sd o/tu7jhc2+r h2/ the resistor in the right-hand circuit?

  10.39: A strong bar magnet is held very close to the onz v)sm wj8tv59ib,r . c7mn(rpening 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 thmr r(sv,97 .vjbminc) zw5 tn8e 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 resisti1i(vhxc -efco: 9jw; qve 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 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 ei :9-qcxovhcjfw ; (1what 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 of the outer cib-lh .;ge ouqmhw 0p )1adb5b3vvb v.9rcuit $R_{inner}$ 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 sa/q31kx9ug0uz:k0u mk y e r7whown, 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 loop sits infwjqrk9 t0d+ o* d9f7i a plane perpendicular to a spatially uniform magnetic field point9t+kq ff*rji 0d9d7o wing 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 convention,- k0l0n2 hku pfdl+z x8mfw(kal current directed up the page. A scientist then moves the loops away from the current as shown. What is the k,0 l0kd lf+ph8-nfx m2z kuw(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 frictionleekf(yh k k50ju2bm( 6dss conducting rails as seen in the figu(2fd(k6hukbmy5 ekj 0 re. 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 at the instant shown?

  08.50:. An infinitely long solenoid passes through the circuit a)wpp ob )0cp/ds shown. The magnetic field of the solenoid, dip/o d)cpb)pw 0rected 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 is decreasing in tjnl:/ 6thnfv us* ru/dp5;h wiq9la+,ime. A constant emf ξ is produced for the square loop enclosing the fr* /5vut ,h d+;aphujql96: / fnlnwisield 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?