94.20: A magnet is dropped through a vertical copp w46wzvld+1ths *kt ;zlnlv ::er pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magnet in the pipe fal:6vtld1+* lwktshwl vzn4:z ; ls:

  01.30: Lenz's law concerning the dh 6,8ys8*45wnp jrqrfd +rug zirection of an induced current in a conductor by a magnetic field u6q dghsr 5 zjr*w,n4y8+8fpr could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is equivalent 4 dvvdwrg pji-l br29 b*+p62gm zp8a+to which one of +zdwvlbgdp pp 9jri8 g4 -r 6*2a2b+vmthe following?

  04.34: A square loop is placed in a uniform magntod1m /j7nkg *z2dr 0hetic 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 o0 j 27gr*hm ndd1zt/krotated 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 tj;zylk vft* ;6he page. The wire expetfj;y*6v zk l;riences an induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves wit vy.c97+is+j1 zrl/w p(lgxbah a velocity v through a magnetic field and experiences an inx(bgc7zl1 wsj.+9ayrpv/i l + duced 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 conductingr-,u)j if/fi5m/ydqj *f-ta p rails. To make an induced currenjd5/iyj/*,f-tp- f aufm )qi rt i in the direction indicated, in what direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic -foy f8*8jd,hq2soyf field has a voltage induced between the wire’s ends, that voltagodho2f, q*f-ys8jy8 fe 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 conuseghwrl z- dj)j .0 )n4 miw3tyap,9g:l9o 7mstant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually eh)a.9-u,rog dg 7 3sy)4:jn09tw jimmzwllpperpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented ck(nb66x+ yy:y k*jwb 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 adde:b cky(j*k + 6bnwyyx6d 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 twkbye1dn 26damm5 d :*o 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 thmd2bkd* :1awd5n6y me is change?

  08.29: A strong bar magnet is held very close to the openinm,a7 xwg cn/3.cb yzl7g 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 sh.,g/ b c7z xn7ywlamc3own and what is the direction of the force on the magnet because of the induced current?

  09.37: For the figure shown, the variable resistance in the ciuoh y)bl6k q p;;f)42m(ioxuxrcuit on the left is increased at a constant rate.kp2byl6uxof);uq4(; i) xmho 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 to the opening of a solenoid w2 n8qwf6 +gbu6v6xh6l ) nrulas 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 which magne2 w6xh8+q 6)6gunwunr lbv6fltic pole does the “??” in the diagram represent?

  14.34: Two circular loophoj a;) trcqb*ke/ +8us of resistive wire are placed next to each other as in the figure. The circular loop on the lef ochjkqt;e8*+u) a/brt 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 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 resisz05sq; j tr 9g/1dyk1qd+vrgtg hk6s5 tance 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 variable resistanlf 4* 8hwmp)ohqvb4/ 1 fd+u:pu: cgwwce 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 sit76rikk6jpl 20 ww dn/ns 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. Whic 6k20dw r6nij/wl7nk ph 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 conventx c*3.wu8hfdjd e3tcd pm,6m+ ional current directed up the page. A scientist then moves the loops away from the current as shown. What is the orient*tw6cd3 ucx ,mmp f 3j.he+d8dation 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 conducto4v/nlg46haztp ww.m4 w6( ziing rails as seen in the figure. Throughout the region between the rails, there is 4 zp/i hv.ngl4mtw4ow66 wza(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 passes through the circuit as shown. Th y 95ej.jnh +,crui:/,hqlmrpe magnetic field of the solenoid, m i,r /le+hnu.hqrc:j,9 py5j 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 pageesm/p fgl.j),c:m, mg d:qtu 5 is decreasing in time. A constant emf ξ is produced for / l5 :gsu:p.mdjcem,gf )tq,m 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?