94.20: A magnet is dropped through a vertical copper pipe slightly larger thuq9 hpr(xp* x4an the magnet. Rex(4qx 9uh ppr*lative 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 current in /yleu 2j,z3myae78zta conductor by a magnetic field could be a restatementt3 u8, zyjele2mz/ 7ya of

  11.25: The product (3 Teslas) × (2 meters) × (4 m2vt x4b0yhgp- b pk4cz2y 1/daeters/second) is equivalent to which one of the followiny ydatxk zhc2 -bv1gp04/b42pg?

  04.34: A square loop is placed in a uniform ec7ml5lk-g h1magnetic field perpendicular to the plane of the loop as shown. The lo5 kgh1-c7elm lop is 0.5 meters on a side and the magnetic 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 dirvz kejqu0(y609r7 p8)* zevadp s9bwbected into the page. The wire experiences an induced charge separation as shown. Which way is the wire mo(k 97rpwd 6bv90su vabejpq)zy ez0*8ving?

  00.20: A wire moves with a velocity v through a magnetic fec wml obrg5 xix;e3qi *zeq5 592*m)oield and experiences an induced charge separation as shown. 5i5eg *q bml;9 )xwmz *5e3rocexo2qiWhat is the direction of the magnetic field?

  05.33: The figure below shows a ik 8)qzuh t71ig9s+kke m jg)7y(d.nq bar moving to the right on two conducting rails. To make an induced current i in the direction indicated, in what direction would the magnetic field be in the area c)dg(7+q9zy q ei 7)tkgk hjm8uni.ks1ontained within the conducting rails?

  00.10: When a wire moving through a magnetic field has a voltagk fpwaj* e 4)aq-q84rpk (r9doe induced between the wir84kqjopd*fpkwq() a9e r-4r ae’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 copper rod has constant velocity 0.3 wy3x1nw4zd6d0 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magneticxz y3 w4ddwn16 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 that its opening k ,djc 0z aor9gr2+p q/be2n.his 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. Rank2aror+kjqhc0 n2z/ be.g,p 9d the circuits for the brightness of the bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the d0*onz;1xjjz5 ( za tpfiagram (which are assumed 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 a0 (jz*xn j5ft;p zzo1right-hand circuit move in response to this change?

  08.29: A strong bar magnet is held very close to the opkqy8 wfg u- pzqy-r:4f-81tbn ening of a solenoid as shown wftp-:z-g k88qfy -yq1rb 4nuin 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 because of the induced current?

  09.37: For the figure shown, the variable resistance in the circuivg.q 56zyvlcm p+(q08 hu8obrt on the left i yh8c(uv+qvbz 6q. g5mpr o8l0s 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 resistor in the right-hand circuit?

  10.39: A strong bar magnet is held very close b/ea(3syu4jp8. w0k lpn1pw qto 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 tj0p (e. b4n1yqswk8/ 3aulwpphe 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 //n.w7k w/qtncx k( s 4 ,tmamu+k.ftkto 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 of the conventional current in t k.xqn/4 m,wk7wn t k/+t. ts/umakfc(he right-hand loop (as viewed in the figure from above)?

  11.41: For the figure shown, the variable resistance of the outer circu.v r3; mnjb r54nstf;tit $R_{inner}$ 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 innoe *f3 qhf uqsnffv497 .z5-qpercircuit $R_{inner}$ 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, condufi 7ej)xg4t/b cting wire loop sits in a plane perpendicular 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 effects best describes theb i4)7f/etxg j result of this field increase?

  16.47: Two small loops of wire are lrl -(kj9e.igejc( or0/c7ofx ocated close to a wire with conventional cukjo9lgr x 0(ie-jc(e7fcro/.rrent 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 occurs?

  17.35: A metal bar is moving to the left across a set of frictionlemnc (k95s 3lkyc c5yssl h0.lw5 :(h/grhz0w yss conducting rails as seen in the figure. Throughout the region between the rails,55cmy0 c gy(ckwshkhs5z3 w0:n9l( sr.lh/y l 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 s-b2cc:yuoxz6k/ 8 twq olenoid passes through the circuit as shown. The magne-q8kt2wz:c yb6u/ ox ctic field of the solenoid, 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 directed into the plk h2yl( 2fpw:bh8s au6ane 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 an:w8f26s(h u lpbkh2ayd an ideal voltmeter connected to the corners through the center of the loop. What is the magnitude of the voltmeter’s reading?