94.20: A magnet is dropped through a vertical copper pipe slightiua8co l) -,xb2 m;uv 0heit0i1x jnu4ly larger than the magnet. Relative to the speed it would falx-x,ic1)v2m0 t ; iluu4bjo0aie8u h nl in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the dh /p.g tomm/fld 61dp,irection of an induced current in a conductor b g.p, /m/hd6lmtfdo1 py a magnetic field could be a restatement of

  11.25: The product (3 Teslas) × (2 ck f kbym7n4dvsl5j3rnv2a14- 2db3hmeters) × (4 meters/second) is equivalent to which one of t1ynvh2d4b bn 4ajkvrfs-2c35 3lmk 7dhe following?

  04.34: A square loop is placed in a unifq5w.cq j5js :rcb9x i7orm magnetic field perpendicular to the plane of the loop as shown. The loop is 0.5 meters on a side and the magnetic f5iwj9 :.5sq7xc cbrjq ield 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 directed into the pageq+amgk8sg jjyl112lckv 7 lg 1:t1 m)j. The wire experiences an inducedk qgvyjmst gj kl8ga+112:lj7m1c1l) charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through karks+.z(ar: 6z loh9q2/bd ga magnetic field and experiences an induced srh qkala gr/d.zok +(:z926b charge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the rsaw*y),a 88nm p4khsspcbi h* 2h8d1qight 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 conductin kbc8,smn*8qp1 ia82*s y)sh4a hhwdpg rails?

  00.10: When a wire moving through a magnetic field has a voltage induced y*rwx4-n/i n 6c3oww,or c zkdel5x9 1between tho o wc*1 6z-nr/lkd xe9w45x,ncr wy3ie 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 copper rod has constant + ru6u:;xvzpag zc38rvelocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potentiag8xprc ;v 63az:u r+zul difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its opening i:n5pa,vif i49n 8evta s 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 add 9ni,p84v:n fiavaet5ed 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 d*v3 fmndrc 8,uiagram (which are assumed to be close to each other), the resistance of the left-hand circuit is 3r *ud8vn c,mfslowly 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 the o7xi fh l ;vwgy.zkfc*4 *0+kldpening of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid at constant speed,.v;lwh0fk ykgfzl* +i4x7cd * 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 resistaqzkl 6-mh8y:;u lru2 pnce in the circuit on the left is increased6y lqmkp;82uu-zh: rl 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 the opening of a solenoid aqushen6le( go: u80m+,1unxnwz9 4bfs 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 in ugzme w8:0,b(xe1qh64nunu n9l+o fsduced 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 to each other as 9 hqvfi r6e 91o6kho7sdb5r2 gin 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 magn 6odb1hs5i7hfr6k 2r ov9g9eqetic 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 resistanc a 4u ndlzv*9(k8h2hpre 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 of the innercircuit kh+avtkjx /d-r: g/+ 3pjxxi1 $R_{inner}$ 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 perp0jn6+nz)j tzzendicular 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 of6n0njz jzt +z) this field increase?

  16.47: Two small loops of wire* wzl5g *-zp26)l1t8ou8xw tpxeiu pj are located close to a wire with conventional current directed up the page. A scientist then moves the loops away from the current as shown. What is the orientation o8-5pguxl*txl 6ez 2o*iu)zj wt p18pw f the conventional current in each loop while this occurs?

  17.35: A metal bar is moving to the lefthkit frg/que 1;;e -yq;3rue+ across a set of frictionless conducting rails as seen in the figure. Throughout the region betwe u3fe+eq q;-/ ;yirgke1tr;u hen 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 the currents through each resistor at the instant shown?

  08.50:. An infinitelo/j 50kg8t:9ggxru zjdrs+ar 7cm, b0y long solenoid passes through the circuit as shown. The magnetic field of the solenoid, directed into thet7 0j0:/do9bgkx j,a gr+rur s85cgzm
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 thz t v-e/ 4(dbtq.ulvk,e plane of the page is decreasing in time. A constant emf ξ is produced for the square loop enclosing the field in the figure. The sq-z,/ e dk( blqt.tuv4vuare 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?