94.20: A magnet is dropped through a vertical copper pipe slightly larger thann c5mf 8ngj9m/ the magnet. Relative 8fjmncg/m9n 5 to the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concern+y rim7 ;c1udjing the direction of an induced current in a conductor by a magnetic field u1r;diymj 7+c could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 mete.01;p7w tdatz; zum9 . izdknxrs/second) is equivalent to whii9 .mzzdd;;u1tan7w 0p xz k.tch one of the following?

  04.34: A square loop is placed in a uniform mamj mvxqar5f69 ;ctl4/gnetic 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 throum9j/lxmq f;vct 456 ragh 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 ma9bodx22smy24 s 6l fwtgnetic field directed into the page. The wire experiences an induced charge separation as shown. Whidly f4x 26 wo29stb2msch way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic fielir 38gl)pojr4g 1an, rd and experiences an induced chargj4p)rr o 1gil,an38 gre separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on))(m* stsdt gvug k7 pi+hn50kn v(b6i two conducting rails. To )(mi kpkgn 7uti tg6d)sh+(nvs0vb *5make an induced current 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 fielde a i2)r2vyprdur 6(h. has a voltage induced between the wire’s ends, that v62i2r e(up.ra dvy)rholtage 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 constay + q1wr/sk jask,2.iant 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. Wha1i qjk+r,a ws.a/k2sy t is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its opening irkj 7cuk9 bp/)mf;8 ybs 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 circuit. Rank the circuits for the brightness of the bulb r7j;/p yb)k 8mkb9cfulabeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (which are assumed to q: cft5v i1r4imz *k a08qx7uibe close to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galvanomikix 07muq8v1 5t :aq*f iczr4eter needle in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet is held very close to the otaaz-12p un o.pening 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 and what is the direction of the 1p .anau-tz2o force on the magnet because of the induced current?

  09.37: For the figure shown, the variable resistance in the circuit on the leb9k9o2ajxqu . ft is increased at a constantaqo2k.j 9x9u b 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 54gce-cm3 yl+.h yvr9vkq vu5is held very close to 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 because of the induced current in the solenoid and which magnetic pole does m9qvyvg-y3cveh45.u kr 5+ l cthe “??” in the diagram represent?

  14.34: Two circular loops of resistive wire are placur5zwu8l+*nxd43 5hyvm 4zx :prsvp +ed next to each other as in the figure. The circular loop on the left is connected to a constant 5lx n3u5 hvmp8+d4w:+zur vrpx*s4yzvoltage 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 resistanceoi8u wf c8k7e.viv ).h 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 resistance of the innerciy2b1 mhu0qhicxdu32* rcuit $R_{inner}$ 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 wiri b1f1zpuve w 74k-j.n9d6b eue loop sits in a plane perpendicular to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field svk wju.b1ude-b6f en7p 1i9z4trength 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 c69lgity 1vi/*jo rr17;jjvtalose to a wire with conventional current directed up the page. A scieor/ri6tv vgja;t7 jl19 j1* yintist 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 frictionlesy h,7gpi( eg60qp8e p8jmvt-ss 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 corre88e syjgtp0m(6q7pp-ve gih,ctly 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. The*d73 zfkd7a q0snhcr7 magnetic field7nfdqdsr*kaz c037h7 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 the plane of the page is decreas(y8xzl z-qy58mth+ux ing in time. A constant emf ξ is produced for the square loop enclosing the field in the figure. The square loop has three identical 8lu( ztyqm-yh8 5 x+zxlight 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?