94.20: A magnet is dropped through a vertical copper pipe slightly larg o5)jx1v0 2exv* sgqeqer than the magnet. Relative to the speed it would fall in air, the magnet i5j q1ve 0g* eo)xqvxs2n the pipe falls:

  01.30: Lenz's law concern5alom9d 2;trl;em b pr; d9r oh9y)f*af5cv0ding the direction of an induced current in a conductor by a magnetic field could be a rtar;hp9;f mbdy)*md 0fed lrcoova 95295 lr;estatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 metecg((dj+cbdblxi9 1 d te52ge b hf.9;frs/second) is equivalent to which one of the bbcgd ied925+9d(ffjx htb c1.g;l(e following?

  04.34: A square loop is placed in a uniform magneti f*/ ;iy*k usrvhbv6-yc 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 stu is*6vfbyhr-k;y* / vrength 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 directu- ri2bwi :g0smhg s6v1-kzz0ed into the page. The wire experiences an induced charge separation as shown. Which way is 0 vk 6sburz--zh:0g2ig1ws mi the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and experiencesi ih0(o8ymor ,aeij+mbs dv- 5v:u10l an induced charge separation ash0+51mebd (v :iu,om0i -svl8 ijroya shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the rightmr4l)az ff+lj ls*u8 4 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 contained within the conducting railz8*a l4)jfsu4lmrf+ls?

  00.10: When a wire moving through a magnetic field has a voltage inducetl x7n2k1lw6y4qn) b yd between the wire’s ends, thatk6nqwy l47x l 12)ynbt 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 zljt-gf(cz,;)ncyss pq *9i 3m/s traveling through a uniform magnetic field oyq3p-,s( igls)ccnz z9;*fj tf 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 opening is perpema*c:(ecv;fgt. :tub32tbj d ndicular to the circu3gda.b2met(ucb t*j f: :;tv cit 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 dimmest.

  07.34 For the solenoids shown in the diagram (which are assumed to be close ug6*v-;if8lret qdm.vs ,57 jmp -kjoto each other), the resistance of the left-hand circuit is slowly increlr .-fj6m- ktjg,8ove pmd*7uq s;5viased. In which 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)est9jrf:y b/ to the opening of a solenoid as shown in tey j9fs)t:/ rbhe 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 the induced current?

  09.37: For the figure shown, the variabugv4maswj 2drh3p9.9 .d dnihe803ldle resistance in the circuit on the left is increased at dhp.u9. 9lewrv8mnhsd i 0j4 g2d3a3 da 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 conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is held very close t cp5htcc9k-o 7clcal1hq2 u85o the opening of 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 beca5cuo2qc 9lccl 7hc a18tkh5-p use of the induced current in the solenoid and which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of resi6de2lwzg y9 hb6*s)p-l a8 edestive wire 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 incre2h dpw*)eb9a-6yezeg6l sld8asing 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 vcm+ fm*4a-bk4axeh ) yariable 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 v ne;s1y d;+e:ggc:6x*abi)gijti h y6ariable 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, conductinbf-l zjk njb475cw- j1g wire loop sits in a plane perpendicular to a spatially uniform magnetbj- 4kbnw jj7l5cz -f1ic 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 increase?

  16.47: Two small loops of wire(d. jd5cwnu (x2t r;6iu) zckx are located close to a wire with conventional current directed u(n5cx.kzu2c r)dd6t ;uxw (jip 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 frictionless conducti(fp) oo2zimz;ng 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 th2)z(mi;fp o oze 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 shown. :tr -2xk mkz/h; 0ulhjThe magnetic field of the solenoid, dir2ujzl;h :-r0t kh/ xkmected 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 direcv 22e l;,zcr one;pk9nm);ba eted into the plane of the page is decreasing in time. A constant emf ξ 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 oe v k92oz;a le re;b2npnm;c),f the loop. What is the magnitude of the voltmeter’s reading?