94.20: A magnet is dropped through a vertical copper pipe slightly vx qs9+zqz.t3larger than the magnet. Relative to the speed it would fall qtz.qszx3 9 v+in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced current in a azf.iq m ,lk2ahyen-+c0akua.121vyf.zso0 conductor by a magnetic field co+1.k yo0 h1fyasqmlz-2 evc.fniaz0a.ua2 k,uld be a restatement of

  11.25: The product (3 Teslas) × (2 m,x2lrkxp sco/-i6xwyrhr x4 ( 09l,bo eters) × (4 meters/second) is equivalent to which one of the fy6 i- ,lrb9o4/, r2sohxkplxx0 cxw(rollowing?

  04.34: A square loop is placed in a uniform magnetic field perpendicular8ie 47o1e nxxi to the plane of the loop as shown. The loop is 0.5 meters on a side and the magxi8 o7nxe14 ienetic 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 directed into the page-8t lxoxwr7mavvk :0 +. The wire experiences an induced charge separation as shown. Which way is +xm tlv7 -:vokwa80rxthe wire moving?

  00.20: A wire moves with a velocity v through a magnetic fan no*nsdk/vz 82t v+;ield and experiences an induced charge separation as shown. Wha+t n8a/n zs*2v;vdko nt is the direction of the magnetic field?

  05.33: The figure below showsc7f)o2jof;b n xmo30m a bar moving to the right on two conducting rails. To make an induced current i in the direction indm3m;fo)jn7o b0xc fo2 icated, in what direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field has a voltage induced betwee 2mqjag 9(6u0s fqts1hn the wire’s ends, t9(s612 ta qmj hfu0sgqhat 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 g2ao1u,r 8 qnx(al*zocopper rod has constant velocity 0.30 m/s traveling through a uniform magn1(rzagol 2u8n xaoq*, etic field of 0.060 T. The 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 thatpt(q3d:;h :u54 l- wdmxizpex 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 frxlp-:wmdq3:p(xez d45ut hi; om 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 a7+ 4r*gprko3f ah1vsfre assumed to be close to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galvanomarp3s7 k1 ov+4rghf* feter 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 al /,fa 7igaiz1 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 direction of the force on the magnet 7la,/ iafig1z because of the induced current?

  09.37: For the figure shown, the variable resistance r-j5uk7 .l(our- t t+tn:zpbdin 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 the rez nou.ur-5p lkb(tdj7 t :+-trsistor in the right-hand circuit?

  10.39: A strong bar magnet is obn d(uga*p,; held 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 directed from A to B. What is the direction of the force on the bar magnet because of thpagu ,o*(; dnbe induced current in the solenoid and which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of resistive wire are0yg6wr( c1 tkop9kqjr7 ,h*)mclwcs) 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 o mskcq(cr79 1 og k))y,l6wwr hjt*cp0f the conventional current in the right-hand loop (as viewed in the figure from above)?

  11.41: For the figure ve .(7ynws(emj: yp(ashown, the variable 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 nxr:gcrg/(f8yp tl )b,rkgj+2t*j/m 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 in a plane perpendiculu r o;e4qh69pltb5mu5:/eqtpar to a spatially uniform magnetic field pointing into the plane of the page as shown. The magneeqt:/o5 e mr9p4b5;hulq6u p ttic 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 tojg;dxw 4h/ hm8c4i6iad8 ufv 8 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 while this occurdc/w vxfi;dhj u886ai48h 4mgs?

  17.35: A metal bar is moving to the lefpt g z5txf6t-9uj0 :qit across 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 magnitudqt-if5:u69g0 t zt xpje of the currents through each resistor at the instant shown?

  08.50:. An infinitely long solenoid passes through the cifqgo 4, kuj 1hll;z1t1rcuit as shown. The magnetic field of the solenoid, directed into the ,uf4oj;qgkz l 1t11hl
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 timey 59xx+ny i:l38 ptn +3vlrbky5nl9po. A constant emf ξ is produced for t9xn5 t:xlro n3+yyib l9y5 kv+pl8p 3nhe square loop enclosing the 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?