94.20: A magnet is dropped through a vertical coppebxx6 yb9z,j h9r pipe slightly larger than the magnet. Relative to the speed it would fa9zhbxb69 x y,jll in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an inducedv(cq0 )rmrvdmh3s6ww(1ce r* current in a conductor by a magnetic field could be a resta6)rc (v1 hrw0sme( 3r wcdmvq*tement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is equivaleny y 0cp2t5*brem1br wj*-j *wrt to t*ycb r0ejrp2* y1r5wmb- w*jwhich one of the following?

  04.34: A square loop is placed in a uniform magnetiej:(5(bc jt ,wn2 wyluc 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 a w (lnwe:yjcu2b( 5, jtstrength 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 fie2e)wogt x+j x4ld directed into the page. The wire experiences an induced charge separation as shown. Which way is t) xjw+42geoxthe wire moving?

  00.20: A wire moves with a velocity v through a mag*.)x23qzel xt c egwc.mn4 rg ddg9+q2netic field and experiences an induced charge separation.2*.2qg 3cqc 9e4ezwxngd) xlrd+tmg as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on two conducting.(i)zjl+lg rix,0 :o osbkb1+3d mc ch rails. To make an induced current i in the direction indiscok(ib.10:+)hr j+mog ,z ix b3l ldccated, in what direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magne5z3bs+i bq 65dnhla8 v )dqgmb:/cbo- tic field has a voltage induced between the wire’s ends, that voltszli3d)nv b5:6cqoqh /a -gmb +8b5dbage 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 0.30 m/s tradjsr7wk y4,,e veling through 4yew, ,jkrd 7sa uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is o 6;mg.jqwnle0 6 lmh c8ir-dm4riented 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 added as shown. Assume0imj6ehn 6m 4lq;w. lrd m-gc8 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 x1 sdy2w2-2d5qn efi83fl kiy d-s)l,yt p9oj(which are assumed to be close to each other), the resistance of the leftn y-8)j i ok,-f5d2fst2 lisdlx deyy32 p9w1q-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 magne7eoyl 1m- /ddbt is held very close to the opening of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid at constant speedld/md -oyb1e7, 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 ler l 7gnt1 lmlznk(4+(85all qhft is increase1 8(m7zk+5la4t(q rn lhl glnld 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 to theu /mp umlsj 3y1m.;m:t 5ceg4b opening of a solenoid as shown in the diagram. As the magnet is/.l3 4:1uumegm mtpy;jmc 5bs 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 qsddjo4 6qq r6 vc17e8r*ns ygrv917kare 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 the conventional current in the right-hand loop (as viewed in the fig691j71rrv7 gnrys * deqcv k 8q4qso6dure from above)?

  11.41: For the figure shown, the var 9 toikl7a/:1lcwpke/t4yt(a c8d a5liable 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 variagpg0 u ) *h8v(i/tp mz4hhun:kble 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 perpendicular t8ju wijl2: zz-mj-gz.o a spatially uniform magnetic field pointing into the planmgljj2 j-wzzu:i-8 .ze of the page as 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 cr *,3.aunf*z h5 q+h:cwfgehmlose to a wire with conventional current directed up the page. A scientist then moves the loops away from h * hcgh+5war,fm.:q3 *fnuze 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 frictionless co qyhilo 6 uq,*r+fz. (ezj2-qjnducting 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 fol-6q.u zh jy+(*o,zijf qlq2relowing 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 pdw+0x(ppvz u3 asses through the circuit as shown. The magnetic field of 3puzw+( pd0x vthe 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 plane of the page is decreasing in tr5 .g;sjhia 3xf n6yj-ime. A constant emf ξ is produced for the square loop enclosing the field in the figure. The square lorsx5y36hjg -nj ;.f iaop 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?