94.20: A magnet is dropped )cd 4roxfet-6through a vertical copper pipe slightly larger than the magnet. Relative to the tf4xr)dc 6e o-speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an inducxq-lc-gx n98jfcvo 76ed current in a conductor by a magnetic field could beq g9nxc c6-f-7j8ovxl a restatement of

  11.25: The product (3 Teslas) × (2 meters9g,b *x msbde)) × (4 meters/second) is equivalent to which one of the9 *,bdxg)bes m following?

  04.34: A square loop is placed in a uniform magnetic field perpe zyuqa )95: 6be.t wrcymdx22dndicular 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. I.ezaq y)u xcwmd9tb26y:r 25df 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 mag1u - i gtv/ ho,unxjdd9b34hl5netic field directed into the page. The wire experiences an induced charge separation as shown tj lb1ih du -ho395/dng,xu4v. Which way is the wire moving?

  00.20: A wire moves with a v r v 3f2*)epqk/0kjj6z nq*jgcx)(yhxi 7gd4 xelocity v through a magnetic field and experiences an induced charge separation as shown. What is 7j*yf* 0xg xpzv q3cq) 4)2dxn/j 6jhekrg(k ithe direction of the magnetic field?

  05.33: The figure below showjubo,f4i kq7f:8 72qm0smue1 p m fm3ts a bar moving to the right on two conducting rails. To make an induced current i in the direction indicated, in what direction would the magnetic field be in the 3f,:ofu7 j0mktm47ies m fq2b pmq1u8 area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field has a vdn+mx 969cg:n so+ wjdcykb7 2oltage induced between th kn++yw6j9 odg29sdcm: 7cbxn e wire’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 velocity 0.30 m/s traveling throughs8su +95lybaehgn/ +a a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What i/bs9l 5e nau+a8g+ hsys the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its opening is perpendicu7pwbwqw +l x46e) tjj703lcqmlar 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 forxq7jm wj647 twl3 0elq+cbw)p the brightness of the bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diaf 6ilo3eany;d c:uu 5foc95/8n( ysfy gram (which are assumed to be close to each other), the resistance of the left-hand circuit is slowly in3 fycla:o(e 96o fy;5yniu 8u 5nfdc/screased. In which direction does the galvanometer needle in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet i16ff9aa8qo c7;z bqzw s held very close to the opening of a solenoid as shown in the diagram. As the magnet is moved away from the soleno8 z7a1c6q 9ozff wbq;aid 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 circuit ofl:e k x.937yiaub9pz n 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 conventional current through the resistor in the right-han 9alzx.e9b7:ufiyp 3k d circuit?

  10.39: A strong bar magnet is held very close to the 1+zzyt b lvi0+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 viy l+ 1+bzz0tfrom 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 fyj .*-oa-pek loops 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 ep *-yjak-.offield 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 exyxbo6 .32amresistance 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 resista5pd*yuc/b4u;rmcsjj frgh / 2- dv) 3vnce 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 xryum5utyv /,- t:7 w:9kbish perpendicular to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnettr/mx: b tsyy7i-uw 5hvuk9:,ic 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 clop 6w : bb8;2uhin3yyfv;wq1ucse to a wire with conventional curren8 ;wifb31byy6wcp h2:uvu q; nt 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 loop while this occurs?

  17.35: A metal bar is moving to(9dn 41jz n*x/mmvjni the left across 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 indicates the direction of the conventional current in the resistors and the relation between the magnitude of the currents through each resij(/v4n 1xm9zmind j*nstor at the instant shown?

  08.50:. An infinitely long solenoid passes through the circuit as showyfndy6 z;g ) 91xfc2 kjxir0m,n. The magne6my2)xzi0y xf9d1 rk jfncg ,;tic 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 fiel-wh);eg,zlr jy8a /v ud directed into the plane of the page is decreasing in time. A constant emf ξ i )ja8zr-lgyvue/; ,h ws 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 of the loop. What is the magnitude of the voltmeter’s reading?