94.20: A magnet is dropped through ah6n9hvn 3d4wgxb-*+pke g /ob vertical copper pipe slightly larger than the magnet. Relative to the speed itd gx/pe4 b9hk+3* w6nvoghn -b would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an inducn0i; vghguyu m(4r6u16 s(1 flett2 fqed current in a conductor by a magnetic field(6 1sqf(0uyu ur46f1h tvt2;ieg nmlg could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/seco8k 2ss2rymr*dulx 0r 5nd) is equivalent to wh *8m0 srd522kruyxlrs ich one of the following?

  04.34: A square loop is placed in a unifosm+a;cdg sx5/rm magnetic field perpendicular to the plane of the loop as shown. The loop is 0.5 meters on a side and the m +gs/xdamsc; 5agnetic 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 p ji7y0k2- c ojc69q.p iql1fha magnetic field directed into the page. The wire experiences an indicy6 j0.oq29pcklh-1i7fj p quced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and 9dru) j hx47mnexperiences an ind d)j4nx mu79hruced charge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bxja ;+dxjq*vg.0j 3 fpar 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 contained within the conducting rail+jvx;qa.j0j*px d 3gf s?

  00.10: When a wire moving trt ,. vkz uu3nl*td v/c,+v9tohrough a magnetic field has a voltage induced between the wire’s ends, that volr*d93u zo .cv,uvttv,/n+ tlktage 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 hz;f:/uupev 9: lxx6ii as constant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity 9l6:ifzpex xi;/u :uv, and magnetic field are all mutually perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is orxjc-ba n+ 40 x,bzxk-ah4q-o.jz6 zoviented end-on 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 added4 xz,obk--+o4 jxv .x n0h-zqc6zajab 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 ar;wl1t gutq8: rh*b d(pe 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 right-hal8ttuhq*d1 ;:p wr( bgnd circuit move in response to this change?

  08.29: A strong bar magnet is held very close to tw5vpfu)0x zba*me3 ghrgl4e(l7o+ i hl w-*w)he opening of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid at e-iuh*7flwl3(w m) z) bhw *plxr0geva+5g o 4constant 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 variab(lqi u3 7f9 s,fzb-fgz gs-*qble resistance 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 left-hand circuit and in what direction is the zq fusglg fis-b *9(-q3f z7,bconventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is held very close to the openfbafg73h c(36cu qv.h ing 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 barf u vqf3gbhch3(ca .67 magnet because of the induced current in the solenoid and which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular lq9f+-fya scd 1y5 9ydg /3pijloops 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 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 s-9cy/y i +3 dfgj5ylp dq91afthe conventional current in the right-hand loop (as viewed in the figure from above)?

  11.41: For the figure shown, the variable rfihqk7l vq5*xj5h5ulan0 *t( esistance 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 resist)9qmdxz7 j;(fx*mzf bance 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 qwcnc*yp5 .t( kv *9x: yz)rsmperpendicular to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strength steadily increnwr9t*(k vzy :5m y)px.q*s ccases 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 cpb)9 8g4 mq sq/kmk+xolose to a wire with conventional current directed up the page. A sm9 pm/b+s qqo xgkk)84cientist 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 fr2)snnzf,eh7)5 th* js .dp nbiv,exe 1ictionless 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,2n) 1d.sehs5e) ninepzv j,h*xfb 7t the currents through each resistor at the instant shown?

  08.50:. An infinitely long solenoid passes through the circuitbl:-zev1 qi-n as shown. The magnetic field of tevz -bl1in q:-he 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 di)n(48q/wnz iw zs)gyug 7mcp/rected into the plane of the page is decreasing in time. A constant emf ξ is produced for the square lowgw)qm)/c /pyuszgi nnz4(87 op 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 reading?