94.20: A magnet is dropped through a ver4;cpw-pdg0 twvgd6 z3 hx)-frtical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magnet in thft0 ;-pd cggrxzvwdp hw4-36)e pipe falls:

  01.30: Lenz's law concerning the dirnq-c20o fcuz +rjp u19ection of an induced current in a conductor by azrcq1cnuu-2 9+jfo 0 p magnetic field could be a restatement of

  11.25: The product (3 Teslas) × n(plj:fqje ddh90-+u5d+si j(2 meters) × (4 meters/second) is equivalent to which+:jidqdjhn0 e9 5 -jp(u +lsdf one of the following?

  04.34: A square loop is placed in a unif m8+)t tb9pqu* bs2:e 5l4jkk41zlx4sos wqrlorm 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 l 4mw 1 lk j4 95tsuzpe:qlo2)sbk+xbtr4s*8q 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 ma f8d. tta:f,,qzswrk -gnetic field directed into the page. The wire experiences an induced charge se8d k,ftf- wrqazst: ,.paration as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a mkvro qu5 4gy/5agnetic field and experiences an induced charge separation as shown. What is the direction of the qkv/ryg 455oumagnetic field?

  05.33: The figure below shows a bar bzn/z 8uc s*y2moving to the right on two conducting rails. To make an induced current s*z/uzy cn2 8bi in the direction indicated, 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 betwehe o301sw:oy een the w3e1:w o0y soheire’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+c+bh )/6il l j,uzouvdhlw,. copper 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 pzl,hldw,+)uv+bh 6ui.jlco / otential difference induced across the rod’s length?

  04.42: A solenoid is+;z;qzuni,9 qzv yg(m oriented end-on so that its opening is perpendicular to the circuiz q ni ,y;vq;9um(z+gzt 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 brightness of the bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diag*ul iviy/w+m( /pjls ol.s c06ram (which are assumed to be close to each other), the resistance of the left-hand circuit is slowly increased. In which direction does t (uml. l i06sc/w/lo sji+*yvphe galvanometer needle in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet is held very qr19y ah f(dxw8ls7 g-close to the opening of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid at constant speed, what is the direction of conventional curren xy8wdfsa qr(h97 l1g-t 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 resistanvg fhc 3*1oktbu8:wm p-t93z rce 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 lvtbo9 tc:r gfu*-z3p3khw18m eft-hand circuit and in what direction is the conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet8q4b6 fmew 7uk)sx4eu is held very close to the opening of a solenoid as shown in the diag4e 7uk)48bqsf 6wexmu ram. 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 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 eacts1pel1t 4 6pqh 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 current in the right-hand loop (as viewed in the figure from a tp6t4plq es11bove)?

  11.41: For the figure shown, the variablpkg *4wefh- wr0fg 9z4 c+1eqme 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 varvnph*4)u pt i:qwv;2h iable 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 perp+fl,flj(h+4zg.jjga+ep :(,jjotr dendicular to a spatially uniform magnetic field pointing into the plane of the page a, gdjj4t l ,ohf(j+jlrfajp: e+.g+z(s 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 t5scxgjb x;gc7/3wym h7zi1lyvk + 85 fo a wire with conventional current directed up the page. Avyjk g;mw8/s zcy7x7x+h lbf ig315c5 scientist then moves 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 of frictionleogufr k,*j5q 0kj6c yz-p39twss conducting rails as seen in the figure. Throughout the region between y9* p-cwgturfkjkq,j03z6 5 othe 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 circqv-* 3 /zx blns/h88l3n azixtuit as shown. The magnetic field of the solenoid, directed into the 8zshnbq-*xz vtli3 x/a3 n 8l/
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 dird7b-(v -fqobq ected into the plane 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 magb-b v-7 foqdq(nitude of the voltmeter’s reading?