94.20: A magnet is dropped through a ve-wrl(f s:v y1xrtical copper pipe slightly larger than the magn lvs -1rx(:ywfet. 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 induced curreno t/qc5goiof (w970iwt in a conductor by a magnetic field 0owq/(f5c97 tiiwoog could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is echldk ,l* 5xei 5oa fa*3-+mj i;elo3equivalent to which oneimdf;j5*aoklel +l3,xece * ih a3o-5 of the following?

  04.34: A square loop is placed in a uniform magnetic field perpeo;6ibn m +4pfvf4jo(u ndicular 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 bffin o o4jv;(+4mpu6the 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 throug8t *ke4x)h8lw (gvmh wh a magnetic field directed into the page. The wire experiences h gte kh8v4w*)8(xwlm an induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetia-31x x*e (d:bq btztj9djn/nc field and experiences an induced charge separation as shown. bjjax- t: tz(3d/9nnbqxde*1 What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to j3+u30t uc ss,e r4zjothe right on two conducting rails. To make an induced curre+ z3 so3jcu0ujret 4s,nt i 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 dy6xg hfsw 2ja34 ehbt;+ iz-zpq5 f:3field has a voltage induced between the wire’s enea6 zdgxh-b h4is;+p fy :wfj3zq2t35ds, 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 con7-dph)a2hv5fmpfp s8stant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, vh p5-hs87vfdpa )mpf2elocity, 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-o8gy4wrm 9-9dwvhf+ bl f2ewd:n 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 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 tlwf9+d8wed f- vw4m 2g by9r:ho dimmest.

  07.34 For the solenoids shown in the pwkj+-ci-u/an, t8kb z)f v:wdiagram (which are assumed to be close to each of,cjp)tva/- bw +u iwnz- :k8kther), 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 change?

  08.29: A strong bar magnet is held very close to 9y(k xak7p,e9vs,d pithe 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 cu xy,97ds eavp,9kik(prrent 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 circuit o .*og5zte(jc vaer88mn 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 circuit8(ezegj5rc*va8m o .t 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 solenoid as shzz4(ytx6-q z +3yxbtu own in the diagram. As the magnet is moved to the left toward the solenoid, a conventional current through the resistorx(y ut 4+ yqbzzz3tx-6 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 regqzels)hokvf,n o84x 12 9ud*sistive 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 wf 19 neu l*8zqoov k)24,dxshgith 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 above)?

  11.41: For the figure shown, the variable resistance of the outer cir01xcrs)1v d ba.2hz zecuit $R_{inner}$ 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 inner6k kekoy2e69rcircuit $R_{inner}$ 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 perpendicula vc5pnz 2h nz; j ;wyg;)x.8/e(bethlrr to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strength steadily increases with time. Which one of the following exvn2/ htl b( nz5 z; ry;jw;.pe)h8gecffects best describes the result of this field increase?

  16.47: Two small loops of wire are located close to a wire with conventionalxr oid5ja;-: 6r7kh ux 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 x5 ouda67hr:rx;ijk -occurs?

  17.35: A metal bar is moving to the left across a; ,yopyk6g :f1tkmy/k dedbmw7: -n7 r 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 identicae 7g mmypt7yfk,:d/kr-:;b noy1wk d6l. 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 l. z0ty+ *8pwowsny x.feodt*.ong solenoid passes through the circuit as shown. The magnetic field of the solenoid, directed into the yd.*f zpt8*s.y+ .no0t wxo we
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 6aqnx0l:;q: m7x . ihgp eg(ekin 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 inn.eqag eki(g0p;6 h7xqlm:x : it and an ideal voltmeter connected to the corners through the center of the loop. What is the magnitude of the voltmeter’s reading?