94.20: A magnet is dropped through a vertical copper pipe slightly largaf fd-4i033 2pg,hurlog 2vp f/nojd.er than the magnet. Relative to t3fpi , /uhofv4n2a0dd r gfo j2-3pg.lhe speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced curreljkven3 )oet4 d t/-aw::hq4 pnt in a conductor by a maganh l:o3 ew vj)4- kd/pett4:qnetic field could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 mejzgl++elj yp 25 wl(2jters/second) is equivalent to which one of the foj2+j2p zlejwg5 l(ly+llowing?

  04.34: A square loop is placed in a uniform magnetic furo 9a6 9bidqc2,znbeky9e.ys/.m2 g ield 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 locg , 2e nd.rib.a so/9 y6zmque2ybk99op 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 direct 07npp.7k o2hu;q tdndu-utl *ed into the page. The wire experiences an induced chpn op7-2tlhku 7 u*.ud;t q0dnarge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v thro3s o4y -g3 1ovwzn9wfqugh a magnetic field and experiences an induced charge separat1vo -ozq9y43 wgf 3nswion as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar mp1 m3ew l7:llkf y(/*vjge6 fdoving to the right on two conducting rails. To make an induced current i in the direction 7*vleflmypk w31/degl ( j f6: 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 field has a voltage inducedq olx2*8nz2qx )fcw ,j between the wirexq *l2n,8x)qcwz fj2o’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 has constant velo tgzl 0:dz/sw0city 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The 0/:zg swtd0zlrod, 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-onll* klrq-w g+rd67: pd so that its opening is perpendicular to the circuit containing the two light bulbs as drawn in figur*p-gll q:dwd6rk +lr7 e 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 t;x1wd, k k5 g(hmh-z *ijb2vamo be close to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galvanometer needle in the ah-k2m,i*vz 5wxh1( md;jk gb right-hand circuit move in response to this change?

  08.29: A strong bar magnet is held very close to the openin i 69onxm/,cpa fnc;e,g of a solenoid as shown in the diagram. As tp oe ,,ia9n6cnx/m f;che 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 variable resistance in the vcm)g)nt;* xrcircuit on the left is increaserxmn*v)tgc ); d 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 conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is helbn.d)m l(isjhk ge:9 +d very close to the opening of a solenoid as shown in the diagram. As the mab9le. ns+mg)h:dkj (ignet 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 xw2abc7r7t, c of resistive 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 increasing linearly with time. As the resistance is changing, what is the direction of the magnetic fitaw77c rbc ,2xeld 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 resistance of r8c;y 4jba jm40(w2 fx8er1x nh8b b;e8 fnaijthe 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 osvxq hudj5n:/f(:kp4 f 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 to a s1 . 8a:wtr gymvw)t5hypatially uniform magnetic field pointing 5ry18wy)m:h.vgwtta 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 are located close5r/vrjex *2+eb,f:3m rztky k 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 conventional current in each lz:yxkfeb+* re/jk3 rvt52m r,oop while this occurs?

  17.35: A metal bar is moving to the left across l v2( 9-y-trx3gymkdegtg*/a 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 and Y are identical. Which one of the following choices correctly -ygxk9dytet-m/2gr( * l gva3indicates 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 + - y; y42)v) zn yhl*dqkf4kyxaj-jaalong solenoid passes through the circuit as shown. The magnetic field of the soleno)+ )a a*-kfy-; nhyjqlkazy2xvyj4 4did, 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 .+pel c9pz/ vdp1ajgs )os 0u8plane of the page is decreasing in time. A constant emf ξ is produced o9ezpp a0uv8s+c/lg pjd.1)s 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?