94.20: A magnet is dropped through a vertical coppe/ctmo2ug6g/ tr pipe slightly larger than the magnet. Relative to otgtum/ 6c2 g/the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an inl,rx )knro52mduced current in a conductor by a magnetic field could be a restate)x l ornrk,2m5ment of

  11.25: The product (3 Teslas) × (2 meters) )u+e r0/y5v oyos*kcan7hzo )× (4 meters/second) is equivalent to which one of the fon) 7) y0hvo/y*u ersa5oz+ckollowing?

  04.34: A square loop is placed in a uniform magnetic field perpendicular to the 36oxg9x3ng4uaa1,cud.w n xr plane of the loop as shown. The loop is 0.5 meters on a side and the magnetic field B has a strengtgdrx,u3 4 9no nxc1 .a6uwxg3ah 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 thee2zi:vsh:0gpg rl t7; page. The wire experiences an induced charge separati: egv; 7str: 0zg2ihlpon as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a hy7yfpapz i :-4b(2pa.w rs5f magnetic field and experiences an 7hpw rz-s452p yi. fbayp af:(induced charge separation 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 railsl3 -atv gg2cx2. To make an induced current i in the direction indicated, in what direction wouldx a-22ggct3 vl the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving tdombq . 7w+ct*hrough a magnetic field has a voltage induced between the wire’sot+7 *dcqb wm. 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 p.xlb whdcc/.h8 *h26f0fdti velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually pe/d0ibx.f c * l8d2cthfh. 6whprpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its opening is perpendiculaikc)2aeytnuj .*3, cli o,u vre- 21tgr 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 uniformly in time at the same rate for each circuit. Rank the circuits for the brightness of the bulb labeled R1 from brightest tnyiccre-)v1jti o2 ,,ug a2*.tu l3eko dimmest.

  07.34 For the solenoids shown in the diagram (which are assumed to be close z7:/2(lc(uf ukksu jeto each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galvanometer needle in the right-hand circuit move in response to tjcf :(kue(/k7 lzuus2his change?

  08.29: A strong bar magnet is held very close to thezk.w 0zp 7 loc2,b+jhg opening of a solenoid as shown in the diagram. As the magnet is moved away from the 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 becl7w h0z kb .+jzc,ogp2ause of the induced current?

  09.37: For the figure shown, the variable resistance in the circuiclwgjwn/84ne+k4f g .t on the left is increased at a constant rate. What is the direction w4k ejg.4lnc+8nw f g/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 solen/ub):fb q(voml-h 8xqf 0l sn,oid 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 and wu( 8bf,bxl-qlmo /: 0nshvq )fhich magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of resistive wia*.rpt8l4/cxq pcj: ere 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 x/cjp8c a.:lp qt*4er 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 q11yzl. gn+hy shown, the variable 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 variab+ p z3p.ei4n nrljt:0lle 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 sits1i siv9 db8zeenz/rn/w l 8t:; in a plane perpendicular 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 this field i rni ziv8/lt/b1ws8 9een;z: dncrease?

  16.47: Two small loops of wire are located close to a wilaz tu,5*bvx)re with conventional current dire)bu*z5v , lxatcted up the 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 ttbh7y1q 6 rwvs ,3em,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 on,3w,ttv7b1eh mqry6se 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 infinitely long solenoid passes through the circuit as hist9zg* w1r+n: 19gkef4 zbh shown. The magnetic field ofzbt1+h4nghz9ef1r: k i9 *wsg the 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 prsw* e d83lsqwu*8yx-age is decreasing in time. A constant emf ξ is produced for the square loop enclosing the field in the figure. Thes-e3r wu 8qydsw8x *l* 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?