94.20: A magnet is dropped through a verti pmwi80u8cf;. exg36iu a+geg cal copper pipe slightly larger than the magnet. Relative to the speed it would fall in air c8peigx;gwm63u i8ae0ugf .+, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced current in a conyj r7iouunb46-ky-fpev +c9 5 ductor by a magnetic field could unu yip-+f ej r6 -9cyok57b4vbe a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/seconzbam; sj(wi29m+sl2hs lz 4d (d) is equivalent to which one of t ;ml+ m22aiwhdss9b4( zslj(zhe following?

  04.34: A square loop is placed in a uniform magvibc y.0n;:nbp ww dbj42nm(q.. hnt;netic field perpendicular to the plane of the loop as shown. The loop is 0.5 meters on a yq;bd:b n 2j.hm; ncnv 40.intb(wwp.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 into bml 1c6 u/ 3a-xgzrm,athe page. The wire experiences an induced charge separ b-,3ca mag1mxu/z6lr ation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and explli s+c(v g1 *iei+b9periences an indlc9l iv(s1i+i pgbe+* uced charge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the righ/6nfx:1,lk3t woy lhoqnej19 t on two conducting rails. To make an induced current i in the direction indicated, in what direction would the magnetic1oeh,3yxfo /nnl9j16kqt:lw field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field has a voltage induced betwee kcam432d7:yhue (+6aq kd7rjwm b5h*ume1 m en the wireu(mamhyk d6hb rm: 7edek4a5w73 *q12cme+ju’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 habh- jm3,.ynt7nu x j+bs 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 i,+by 37n-jxm nu tbhj.nduced across the rod’s length?

  04.42: A solenoid is oriented end-on soeair . u1.c1fl 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 e.fi1.ru c 1lain 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 (which ar t;d))h04xi 8m va*r ydwvybo9e assumed to be close to each other), the resistance of the left-hand circuit is slowly increased. In which)9yvh4)8 0voax*d;rw mi ydtb 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 opening of a solenoid a p 66yzbvk6r,ns 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 because of 6 yn6bvrzp,6k the induced current?

  09.37: For the figure shown, the variable re16 osxzju vb3-sistance in the circuit on the left is increased 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 cv1o 6b zs-uj3xonventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnetf: ij7,p33a7p4o t:jrr lzkj t is held very close to the opening of a solenoid as shown in the diagrap:j ,f4 kj7r 3t3loa:r7tpj izm. 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 which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of resistive wire are placed next to v l,vy*c3 o3qgeach other as in the figure. The circular loop on the left is connected to a constant volyv*vo gcq,3l3 tage 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 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 variabsv z ce0ah) /e7kv+d82idw 4itle 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 figurrr l7y*i(m;k1/adwa te shown, the variable 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 perpendicular top o)e;pdxawiu42 -x2 +mw+fmqp-wh9 l a spatially uniform magnetic field pointing into the plane of the page as sho+2xlp9 ;ip) u a pf --demwq42xwwom+hwn. The magnetic field strength steadily 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 i7std re4wcqx /xi5-2el w/ io7u6-nfconventional current directed up the page. A scientist then moves the loops away from the current as shown. What is the ori4s-rl/iu/c5i f7 6e-2d exwto n7qiwxentation of the conventional current in each loop while this occurs?

  17.35: A metal bar is moving to the left across a set of frictionless condz;7b akc:sz4bucting 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 aresz7b4;zkb c: a 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 pa*v zst8azlktm 1 e)ac 22b2k4ysses through the circuit as shown. The magnetic field of the2k2ec*za1)m tv2t 4zs8 bkaly 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 page is decreasing in tvk 4w*az,bkk9ime. A constant emf ξvzw,9 *ka4k bk is produced for the square loop enclosing the field 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?