94.20: A magnet is dropped through a vertical copper pipe slightly larger7s f,8d.j89vg k sht7g))0pvvhdns me than the magnet. Relative to the speed it would fall in air, the magnet inv s)8,jhpnvs97s h8 .)k7mvegdtd0f g the pipe falls:

  01.30: Lenz's law concerning the direction of an indvig gcvyw)4 y5 o6.)whuced current in a conductor by a magnetic field could be a restaogw)c w yv.y5)g6h 4vitement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/vyh*yia/pz k:hz , 5y ,rj0p8csecond) is equivalent to which one of the fop 80pv/jy z5 yzyr:,kh*ahi ,cllowing?

  04.34: A square loop is placed in a uniform magnetic field 0lc x3ej)a: njg0k5t3uwnl6s perpendicular to the plane of the loop as shown. The loop is 0.5 meters on a side and the magnet )jslekju glw30 nn: 5ax60ct3ic 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. The wi30alhp:ok y -qx6qze2 re experiences an 06hakql ey3 zq- xo:2pinduced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves wi*xw*yo1ea yo r8tir 9+oo *k(rth a velocity v through a magnetic field and experiences an induced charge9iow o orr1*8(t+*kyoeaxr*y separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar 6l7nnhjy(p( v moving to the right on two conducting rails. To make an induced current i in the direction indicated, in what direction would t6(pvlynnj h 7(he magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving th beyz3mbi5:*nrough a magnetic field has a voltage induced between the wire’s ine b 5bm*3yz: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/s trarozj/7u n4co;9wew; +e;j6 j ;)gdy fzhtmc+ oveling through a uniform magnetic fiewu;+j9 z6jtoz oncmy;h;fg4j eced+ ) 7/r;o wld 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( z ntzeuv l(92zq;6ay-on so that 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 thz2ytzzu(6n; veq( a9l e 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 diagram (which are assumedrnuid6da+578w up2qj to be close 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 in response to this char u+pni7 6qjaduw8 5d2nge?

  08.29: A strong bar magnet is held very close to the opening of a solenoid (sp,qwws ye2qltdl7zp87o1) 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 sdo eqs(sqly ,)w 87tw72z pp1lhown and what is the direction of the force on the magnet because of the induced current?

  09.37: For the figure shown, the variable resisv b0c l6hd(c)7f ihu .k07cgzoh 2gj8itance in the circuit on the left is increased at a constufg 67720 cjhhogh8 vcb 0dic (z)l.kiant 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 opening of a soa x4mb,5b3to j.)ne16mh7iwkau f :dglenoid as shown in the diagram. As the magnet is moved to the left toward the solenoid, a conventional current through the resist,hju1o:b5)wf7 6etmm.4b 3k agxnaid or 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 magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of resistive wire are placed next to etx rvbgg) jb/)(cl1 c.xoy+ b:ach 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)t1j(lcbbc/gxgbv ry x)o+. : ) 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 shhtcbjfy 1v*h-) qp gu34p cq3j7mk0(down, 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 variab5 gzby/e,kketd3 u5l )le 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 perpendiculareeo+:i.)qq5 efhoj iv(0 t4is to a spatially uniform magnetic field pointing into the eoj4.o5tq q 0hfs i:i(+i ee)vplane 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 4o er5r/;xokbconventional current directed up the page. A scientist then moore 4 ;/rb5kxoves the loops away from the current as shown. 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 r*.,rxje8sji f- q6 : f(hnzvgof 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 thzxf6qj rs(g,nj* ire-.h:8v fe 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 solevfid9ac ct+ob0p*7o* noid passes through the circuit as shown. The magnetic field of the sov0f*it pcbc7a+ 9do* olenoid, 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 ehyhd,v6 -/7 :lsu)qenhnqfk dx+(5 i directed into the plane of the page is decreasing in time. A coni:- h,hxq5qy ldd /k hene(svf7+ nu)6stant 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 ideal voltmeter connected to the corners through the center of the loop. What is the magnitude of the voltmeter’s reading?