94.20: A magnet is dropped through a vertical copper pipe slight e lc+2nv;mqr(ly larger than the magnet. Relative to the speed it would fall in air ;+mel2vr qnc(, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction ofh45 bp .;py,opf79 dozbwbf1kvfh)5r:tr pl6 an induced current in a conductor by a magz 54b );f:oth.kv 7p1l hrdpbyow6ff5p,br9 pnetic field could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/sec e7vmvwgd8 ,*gond) is equivalent to which one of the fov* m 7gvd8egw,llowing?

  04.34: A square loop is placed in a uniform m,- )epaxw5v rdagnetic field perpendicular to the plane -a5)xwd,prev of the loop as shown. The loop is 0.5 meters on a side and the 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 intr tx5*s;dpi)j5w;2 i39 i p8rvyrttut fc:ss3 o the page. The wire experiences an induced charge separation as shown. Which way is the wirxs 5trprsr;ywf5vdpi t i2*:t983uti 3c )sj;e moving?

  00.20: A wire moves with a velocity v through a magnetic field and experiences g: p-cvl7a pt5 dlz8zaz2tda, .zi,/ean induced charge separation as shown. What is the direction of t/lale at zid:at z 7c2pzv.8z,gd,p5-he magnetic field?

  05.33: The figure bebjhjf tavr+st(;n3+8 k4dogy aiv es;38e.z, low shows a bar 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 c+kn v(t8zjdvs;r+i8a;a.gobjf y343 t, hseeontained within the conducting rails?

  00.10: When a wire movingknqhv h:*3dpgb5 km 8- through a magnetic field has a voltage induced between tph:v *8-5k qnmhdbkg3he 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 velocity 0.30 m/s traveling throug9 9lp+eicoqcp8e6k* bhhu)6 jh a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are j* cbiek8cehl pup)+ 669 oq9hall mutually perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its opening is perpendbtd7,qn-3 i.ijr-8 pev wdmz* icular 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 to dip t -i*,bwqzmd-e.3dv 7rj8in mmest.

  07.34 For the solenoids shown in the diagram (which are assumed to be clol1crbo :e dzpt(0t2m*pcn :: pse to each other), the resistance of th::* cr p0obtn(: cd2zltpp1mee left-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 magn;-ti lt :k.muhq m90cu 2zmh5cet is held very close to the opening of a solenoid as shown in the diagram. As the magnet is moved away from tlc. mqu;0-uc ktim2hz59 mh: 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 because of the induced current?

  09.37: For the figure shown, o vb/58ztqo b)the variable resistance in the circuit on the left is increased at a constant rate. What is the directiob58 vt o)zqbo/n 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 as shjxm501nuzz8ha y3 w 9zs.xmi9own in the diagram. As the magnet is moved to the left toward the solenoid, a conventional curayxxz 3h8m0m9ziu9 s.z1nw5j rent 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 arkm(6gb75udwj6 pg- (z0ks-zex h opn( h/9qpy e placed next to each other as in the figure. The circular loop on the left is connected to a constant voltage source V. The res-xmqp pb6n57g 6eo9u- ( kyg0 szpw((hk jzh/distance 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 figure from above)?

  11.41: For the figure shown, the variable resistance of the outer circuita*(bat5j)3.bsxj 5 yzh m(ums $R_{inner}$ 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 vmv 0 1bm2vyk5eariable 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 loopo ,qm d:n.)mki sits 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 timdk o.mq,in:)m e. Which one 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 w,ueb2j41g p0ov5ygibj8d c /f ith conventional current directed up the page. A scientist then moves the loops away from the current as shown. What is the orientation of the conventional curren2uoeb5j g8v,fi 0yjdc4p/gb1 t in each loop while this occurs?

  17.35: A metal bar is moving to the left across a set of frictionless conducti3 my+loi hc-4lng rails as seen in the figure. Throughout the region l -iho+m cy3l4between 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 infinitely long solenoid pas(l kjj /+dsj,fses through the circuit as shown. The magnetic field of the sl(d, j/j+kfjs olenoid, 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 fie;e4qbzgac l:b,o 5v vlm,8o5von+ry7ld directed into the plane of the page is decreasing in time. A constant emf ξ is produced for the square loop enclosing the field in r +5oavv ml7q:vebc y o 48gb,5no;,zlthe 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?