94.20: A magnet is dropped thdti9,n3b,7 -sofdnti7e , hrc rough a vertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in hi ctb7i3-9,drnn,,s etodf7 air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced-o-7kpa5libn mr a3( h current in a conductor by a magnetic field could be a restatement a-(r on7mlapi kh3 b-5of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is equivalb2ay*dk4jyf j;c 2mk2 za5+h kent to which one of the follkahy+*2 d2 az;42by5k kjmjfcowing?

  04.34: A square loop is xzz2l 5g)1fn;glw *aj placed in a uniform magnetic 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 an angle oj)anlg 5z gwl12z*xf;f $90^{\circ}$ in 0.1 second what would be the average (RMS) induced EMF in the loop?

  97.32: A wire moves through a magnetic field directe*1o ytm nqs9y8ah -y2od into the page. The wire experiences an induced charge separation as shown. Which way is the wire moving?qs8- t9y2n 1o m*oyhya

  00.20: A wire moves with ckb3 32o9t5y(nvor lg a velocity v through a magnetic field and experiences an induced charge separation as shown. What is the direction of thet(l3b 3v9nokogc 5ry2 magnetic field?

  05.33: The figure below shows afi4(xd wx, :by bar moving to the right on two conducting rails. To make an induced current i in the direction indicated, in what direction would the magx(iw4d,yx fb: netic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field has a voltage induced be uh9:yof9jc 5rsd/l9-mk qm, q8 lonz5tween the wire’s u ,mlfso9q5nz9/m:chld9y j q5r8-o kends, 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 veloci*f5w4jkisp6f q7nzwmj8 h 3+ jty 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendiculjk 4+fi*mw s3wn587hpq6 jzfjar. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so t-spv ol 7mb(2uhat 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 (p 7buo2m -svlis 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 assuclk2 ; hzy g*+cb*,yzomed to be close to each other), the resistance of the left-hand circuit is slowly increased. In which di c2g +k;,bhcyoy*zlz*rection does the galvanometer needle in the right-hand circuit move in response to this change?

  08.29: A strong bar js p q b4t )5-vfxjjrj(srz1-9 kog12ymagnet is held very close to the opening 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 shown and4 j1txfy ) r-- pzg2kvqjjjbr(15os 9s what is the direction of the force on the magnet because of the induced current?

  09.37: For the figure shown, the variable resistad88a 3tqq yd5jnce 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 convent385q 8yt jqddaional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is held very close to the opening of1l x4scx,hpby+(;f:otq xpp5 a solenoid as shown in tppfpos c:xlbt; +xh,54q(x1y he 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 magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of res )yn.jr.dyn49j8g ihmistive wire are placed next to each other as in the figure. The circular loop on the left is connected to a constadnj94.h nj y8m. gy)irnt 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 resiskqcg hm5lw -0-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 ,0j c5dnaxsc2k8 q.- s(rwqpo0q0wzz 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 perpenvx ev;2*bf q7zdicular to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic fiel2 f*7q;ezbvxvd 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 lkpkdr t2+6n( .jk)qzare located close to a wire with conventional current directed up the page. A scientist then moves the loops away from the current as shown. What is the orientation of the conv.qjnklz+drk)p 6 k2(t entional current in each loop while this occurs?

  17.35: A metal bar is moving to the left acroerw9 w(;bxnb py 1uy*,ss 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 a(uwpwyn b e y*r9;,1xbnd 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 thetz5ab0g0 0vb x circuit as shown. The maav0zb0g t05xb gnetic field of the 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 ca7om/; p na4bthe 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 l7bpnac /amo4; oop 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?