94.20: A magnet is dropped through a vertical copper pipe sreur9;1bqn d- bw45hp lightly larger than the magnet. Relative to the speed it would fall in air, the magnur;pd w9 eqnh51r4b -bet in the pipe falls:

  01.30: Lenz's law concerning the 0icdedzx 4-3tw)j/f ixe b/ thbuh7l j4;q1g, direction of an induced current in a conductor by a magnetic field coubi qiezge17044- bh),jjl/ /xcx fdtwd ut ;h3ld be a restatement of

  11.25: The product (3 Teslas) ×t-dln 4 yn1 *(iyzdnv( (2 meters) × (4 meters/second) is equivalent to which oldn*nzinydv(( 14y t- ne of the following?

  04.34: A square loop is placed in a uniform magn y2i/ptrzd*t, etic 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 strength of 2 T. If the loop is rotated through anipt,y/zdr*t2 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 page. The wire hbn iw(im)rxzh d 6g ea)k:u)+94q5m7j: g njiexperiences akz n5( g)e)ujngdrxwi4i:qbi) 9h 7m+ am6:jhn induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves wiru 4wu 7d*vi*yth a velocity v through a magnetic field and experiences a4*wriuv*duy 7 n induced charge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below s zdm30u;zi uz1hows a bar moving to the right on two conducting rails. To make an induced current i in the direction indicated, in what direction;0z dz 3uiu1zm would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnehyqes;0 n j q,-3o,rhr.;yej7 ixn;zwarh q +(tic field has a voltage induced between the wirq;3r- hjsni,jn yhrh+z(0e yx.o7,w; e qaq ;re’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 coppchw* ecn b:;*duwn7*ger rod has constant velocity 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 potential difference induced ach:*n;c*b *w udegnw7cross the rod’s length?

  04.42: A solenoid is or ttf3rapbm:s e2(y g ivqw2884iented 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. 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 circ2bwtvm3psge28 qi(t8r yaf:4 uit. Rank the circuits for the brightness of the bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids sh9oo j0roan+ 4down in the diagram (which 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 in the right-hand circuo+a9o 4 dj0norit move in response to this change?

  08.29: A strong bar magnet is held very close to the opening of a solenoid agga9 r;x5) mvqs 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 vaqg;5 xg mr9)because of the induced current?

  09.37: For the figure shown, the variable resistance in the circuifwc/n( ;) +2 fp)gvnf jpae,cb6dh+gkt on the left is increased at a constant rate. What is the direc gn 6;dfjewb2+ff+),g)v nc/pakhp(c tion 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 sole v2yl):zwhn k*cgb xx7: 9bw/anoid as shown in the diagram. As the magnetygw)nh v2 k9/:b7cxxb*l:z wa 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 which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of resistive wire zemnyo658ikp ,t n/j/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 magnetic field at point P (the center of the left-hand loop) and what i/npje,ty/i o86z5 kmn s 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 lw+te1(r.:dqrk9v 4)ipovixouter 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 resilc0jkj)6p/ zaonui+0p 1d3ze stance 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 to a s4n rkj h5f76wzpatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strength 5r74kn z6fjhwsteadily 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 close to a wire with conventional cej ir+h( 3qpw)urrent directed up the page. A scientist then moves the loops away from the current as showiwj(h epr3q )+n. What is the orientation of the conventional current in each loop while this occurs?

  17.35: A metal bar is movinvhb ti4owi-vihdj2- 7oz9/ f9g to the left 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 resist9 hbihtd9v o4-/j-o zvfw i7i2or at the instant shown?

  08.50:. An infinitely long solenoid passes throunsl4/pnrp9u (gh the circuit as shown. The magnetic field of the sn(p 4lnp s/9urolenoid, 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 deps9 :-wf;2lhsrunsr 77g9tx g nkfm 5*creasing in time. A constant emf ξ is produced for the square loop enclosing the fieldsh gr*f 7n2m9r7t:nkpu-g ;5xss 9lw f in the 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?