94.20: A magnet is dropped through a vertical copper pipe slightly r6orzti* 65bl larger than the magnet. Relative to the speed it would fall in air, the magnet in the pipez5 or*lr 6itb6 falls:

  01.30: Lenz's law concerning the direction of an inae(douqa(m) ntd- *)bm+hu4 aduced current in a conductor by a magnetic field could be a restatement tauq)4mum(d ban+oa d(e*h- )of

  11.25: The product (3 Teslast 8*q fh izl3-qjzd-u/) × (2 meters) × (4 meters/second) is equivalent to which one of the foll-il hu-8 qzdzq/j t*3fowing?

  04.34: A square loop is placed in a uni0dcjlh 9 (9gdmform magnetic field perpendicular to the plane of the loop as shown. The loop is 0.5 meters on a side and t 9ghd mc(j09dlhe 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 directed into ,:wp 7:d+i0sml)llxqzrc,dtw d h g6/zp cq ;1the page. The wire experiences an inzd,qslhl zr t cc+6p/p:;dxq,wwli 7g:m0d) 1duced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and experigiuu02b i8;vnv,a 0jhences an induced charge separation as shown. What h0 v0i;vi8ag, ujb2un is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on jts u3 1.ppx /og87zvrtwo conducting rails. To make an induced current i p8t7 j.gpuv3/ ro1z sxin the direction indicated, in what direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetc)d 0)pvd:si wic field has a voltage induced between the wire’s ends, tscd pvi wd:))0hat 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 const/0ggef sw r+hf,86sx want velocity 0.30 m/s traveling through a uniform magne fregsx0w 8 /+6whgfs,tic 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 oriented end-on so that its openin-e3wpyp,g0 xf:s bjb039u jyvg 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. Assume that the magnetic field from the solenoid, shown coming out of the plane of the page, decreases unify 3bw0,pjfpxe3-0j ysv: bg9uormly 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 (wf4,ax:1iqhs ihich 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 i i:q aixhfs4,1n the right-hand circuit move in response to this change?

  08.29: A strong bar magnet is held very close to the y f,s4vu-o)hiopening of a solenoid as shown in the diagram. As the magnet is moved away from th-, vyu4hsoif )e 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 circuit on the lfr)sz o1 1pe*jeft is increased at a constant rate. What is the direction of the magnetic field at the p1sefr *zjo1)p oint 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 k2eg3i78kbd8v9 a0ojoi i,p vof 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 the induced current in the sol2vooe ,igi9 8p ja 7ikbk3d0v8enoid and which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of resistive wire are pl1l f-l)z6xq o kr5qdq3ix6 )dzaced 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 6o-6d3 lx qxq izrd)f z1q)l5kthe 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 of the outer cirdlnu01zb 0t7 ycuit $R_{inner}$ 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 variahx;f*h4 xayjl5su -3bble 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 pe t77(ye j-n5,r jj3xsyy9cu utrpendicular to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strength steadily increases with time. Which ons7y unj 93-uyjt(j,t7 rxe 5yce of the following effects best describes the result of this field increase?

  16.47: Two small loops of wire are located close to a wire with conventional 4(qd4z1dng kyz/pzvi uh) p16current directed up the page. A scientist then moves the loops away from thkq644p) u1i d/z1vy(zngd ph ze 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 levd0,l.age:y 42vow y s)dky stw6ne 5)ft across a set of frictionless 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 the currents through each resistoaeked45)n: yyl gt)dswvov6w 0, s.2 yr at the instant shown?

  08.50:. An infinitelyn8k1lf,lfn m p3uikr 9b7a8 2a long solenoid passes through the circuit as shown. The magnetic field of the solenoid 17ap3nk 8nli2l af9,krb8 umf, 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 thevcp8l0m3z2 s h ja/m+v page is decreasing in time. A constant emf ξ is produced for the square loop enclosing the field in the figure. The square loo c +j2vhzl 3/ps8mamv0p 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?