94.20: A magnet is dropped through a vertical copper pipe slightly larg,y1h.zrkq, gb er than the magnezgbrh,,1 y. kqt. Relative to the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induyn0m 8j-:ysu5 -azlf gvpe *c,ced current in a conductor by a magnetic field could be a restam*ns8,cpu zjf0lg a e:yv- 5y-tement of

  11.25: The product (3 Teslas) × (2 meters) × (4 tw*x 5uorkf0* meters/second) is equivalent to 5f0ku*twro*x which one of the following?

  04.34: A square loop is placed in a uniform magnetic fiegr:xa2jmr h4d tb*- ovv(6+meld 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 strto * (-rvdgea42bmrhvmx6:j + ength 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 pa*h2 r,bk tq+xz av6t7dge. The wire experiences an indux ,batr7kt 6 dq2z*+hvced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and expe bje6lwa(oc20riences an induced charge separation as show0 jca (o2b6elwn. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the r9fo7 zqxq vg84ight on two conducting rails. To make an induced current i in the direction indicated, in what direction would the magnetz f9 og78qxq4vic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a ma5* oh182zedh2za lbncgnetic field has a voltage induced between the wire’s ends, that voltaged8ez2 2n hh5c*aolbz1 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 coppebagr pvir2s5 :0dy83). hxedn r rod has constant velocity 0.30 m/s traveling through a uniform magnetic 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 lengthr0: prx2 i5sv)dheb8yn ga3d.?

  04.42: A solenoid is oriented end-on so that its opening is perpenupt( ml7 hqg.xd4g c*(dicular 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 uniformlgt 4.lmgcuhq d (x*7(py 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 s gzko*.2, /zvvbt 2edyhown in the diagram (which are assumed to be close to each other), the resistance of the l2tevok2 . *gzb,vdz/ yeft-hand circuit is slowly increased. 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 ,po ) idrd mr*mblud((ryr4 4(of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid at constant speed, what is the direction ofyd ,(irdr(rm*r4(4bumpod ) l 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 circubw (t9gee ;,qe ,yo*auit on the left is increased at a constant rate. What is the directie(9*eguaeo,t yw qb ;,on 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 e nko. q2tf 18/n3+blhv2 m:nr 0erbhjheld very close to the opening of a solenoid as shown in the diagram. As the magnet is moved to the left toward the st ho m8h3qnrb:2vk/en.er f l jn20+b1olenoid, 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 the induced current in the solenoid and which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loopchk7oiz bxg 17z)7)t.v :dbrms of resistive 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 b)h7:r)1zzm.ix7cdt gk7bo v 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 varig/ h6p+u+oel8( ccqfptrsva -fc4f18;qrly,able 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 resistance of the i z:a0xwhbhs;vu7ly+ o9 nad)/d 2 y 1hshr.ni(nnercircuit $R_{inner}$ 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 perpendicular to a spatilt02 jx*ktm+w*b pd) sally unifwd 2jl)b+pk xt0tm **sorm magnetic field pointing 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 conv2 m- zq,svvyk;entional current directed up the page. A scientist then moves the loops away from m,svz 2 -yv;qkthe 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 of frictio.cvteyt -1(g v69ko o oo6 7uev/0h:t9jbgkjxnless conducting rails as seen in the figure. Throughout the region between the rails, there is a uno.kvh9 g vvg:y kobjte61t0 (j /9eoxt o6-uc7iform 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 passe/uu31k6 agxxa s through the circuit as shown. The magnetic field of the solenoid, directed xa/3uk 6x1uag 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 planr iz*66zzx( yne 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 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 readii( xnz 6*ryzz6ng?