94.20: A magnet is dropped through a vf4k9at y gq4;zqac;/ aertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the maf;;zaqaqy4/ katgc 94gnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced current in a qed 7htrmzwa 7kgz/xaxk/ +(86l 7 bg2conductor by a magnetic field couldt + (72e6xlbkg/hdak7gx8 a/qmrzz w7 be a restatement of

  11.25: The product (3 Teslas) × (2 meterjgr0-jp)x h ,rs) × (4 meters/second) is equivalent to which one op j,r)0h gxj-rf the following?

  04.34: A square loop is placed in a uniform magne35-bs z e9q6 fj9n1 gle*tqwomd7 :gfytic field perpendicular to the plane of the loop as shown. The loop is 0.5 meter9 eqgnq -egmy *9sfbf 3:7w6dz51jl ots 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 div5o k)sj 9t/jrrected into the page. The wire experiences an induced charge separation as shownt/ov9)j ks rj5. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnet 8 o/sitod4a )2qx*4l26gyrdoq k.jelic field and experiences an induced charge separation as t o2qler)g.oqd246sij a 8dkl4x *y/oshown. What is the direction of the magnetic field?

  05.33: The figure below show 4v ap;caex(4:5c:)6l/ txbkoqmvxzts a bar moving to the right on two conducting rails. To make an induced current i in the direction indicated, in w( :4x pvba )x veal65occxz;/mk4qtt :hat 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 ky* 4cab4qx0cvoltage induced between cx4 qka4 *0bcythe wire’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 gvupj,wigdp77hf:9- opper 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 7vd hf:p-i7gw 9pg, juall mutually perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its ofw +d/8gyt xw:pening is perpendicular to the circuit containing the two light bulbs as drawn 8t/ wdw gfx:+yin 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 diagram (which are assumed to be 1 xupz:qdz,b1n ( v4muclose to each other), the resistance of the left-hand circuit is slowly in 4un bq(u1z dxp:mvz,1creased. 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 ofe ipf j1nb3lwz(ar+ -)+8iab g a solenoid as shown in the diagram. As the magnet is moved away from the solenoib+na1z( g3bfij-l +r)8awpie d 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 circuit on the leftwait ,kqc we./y45 zjg5b4.zm.x xp2 k is increased at a constant rata tpzb jzweq,i.4cy5km/ 4 . xk.g52wxe. 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 sol)xyy)t6cy k/p enoid 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 the induced current in the solenoid andy)cy)kx/6p y t which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of resistivtyw lhrnr47; kp vpqb0:e9n1 4e 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 e7w91 klrn0b4 t; vn:y4rphpq 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 above)?

  11.41: For the figure shown, the variable resistance(m20ft; w ccgw0c (tob lvqo+: 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 nmw(;t6:v2-k4x4w:drf,mlxd q asizp)+ nggof 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 perpenya./x :7 vsfjwdicular 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 the result of th j/f :yavs7w.xis field increase?

  16.47: Two small loops orcz:s ;m )tmo/f wire are located close to a wire with conventional current directed up mz ):;msocr /tthe 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 friction1dkzb*4r a5ytless 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 the conventional current in the resistors and the relation between the magnitude of tk4ar5d tz*1yb he currents through each resistor at the instant shown?

  08.50:. An infinitely long solenoid passes: *q3 dt* tqubn:sp7zi through the circuit as shown. The magnetic field of the solenoid,udt: :n * tpi*3s7qqbz 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 plane of the page is :f6p 2guwufs 7decreasing 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 w:fsuup6f2 7 gthe corners through the center of the loop. What is the magnitude of the voltmeter’s reading?