94.20: A magnet is dropped through a vertical copper pipe slightly lakn q6fj7 r)k6o g6fdjf.;x0jv rger than the magnet. Relative to the speed it would fall in air, the magnet in the pipe fal6)j7kq6.fj;rn x6djvkf g o0fls:

  01.30: Lenz's law concerning the directi wbtzfp0 9vh53on of an induced current in a conductor by a magnetic field could be a restatement b03wfh9pzt v5 of

  11.25: The product (3 Teslas) × (2 meters) × (4 mete)mnhtfx+di. 5l( js80ppn otws t(8a1rs/second) is equivalent to which one of the fo.(a8t 0t8+nxjd ts 5im 1o)nlphfps(wllowing?

  04.34: A square loop is placed in a uniform magnetic field perpen*njzevx 8k+/i dicular to the plane of the loop as shown. The loop is 0.5 meters on a s+*k /vjinx z8eide and the magnetic field B has a strength of 2 T. If 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 magnetic field directed into the page. The wire 1da(8qj e x-cejv+jx-experiences an inducjex ae+-qj1 j cd8(-xved charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v th.6 kxixte r;/hrough a magnetic field and experiences an induced charge separation as shown. What is the direction of theki; .re /thxx6 magnetic field?

  05.33: The figure below shows a bar moving to the right on two conm25k x bl.dy )mg,kg9gfxu9v 0ducting rails. To make an induced current i in the direction indicated, in what direction would the magnetic field be in the area contained within tg9l. 2fb9mgudm0 xgv5k) k,x yhe conducting rails?

  00.10: When a wire moving th if9;0l0e-ink4vrw4x gawj(y rough a magnetic field has a voltage induced between the wirev- y4exnl0w w0k;ra i9fg(j4i’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 haf0cog27j r iohh5w06p ysc*w4 s constant 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. 6r* hcy 0ow74cfhogs5ij2w 0pWhat is the potential difference induced across the rod’s length?

  04.42: A solenoid is o*8 9nc z -r6)lvtjnd( e1dspcxriented 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 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 dcnsxd c 68(v1t* 9pe)j-zrnlof the bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (which are assumed to be close9hrzn)a )s s3b to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galvanometer needle in the r)z9 sb)rsn3a hight-hand circuit move in response to this change?

  08.29: A strong bar magnet is held very closn9q ;x -dskta0e to the opening of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid at constant speed, w d-9; sntqa0kxhat 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 variabl4jrr :teb: tojfx+ 6 3q5ad9gle resistance 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 conventional current through the rest+og:lajq4jb f5rxt3r:e9 d6 istor in the right-hand circuit?

  10.39: A strong bar magnet is held very close to the opening of a solenoid q(b)of / 2oqdwas 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.qwood 2( /)bqf 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 resisti uai4;vkdnns +aqh4h-7ub1l 6ve 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 magne1qbnaa-n44 ud6hk ihu+l;7svtic 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 resistance of the ou1scay0vezab /d-8l j).x, o:e md l8fnter 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 resi9fb.gm4zr,b6p wp+r nstance 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 loop154q ttrj i4wa sits 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. Which one of the following effects best describes the result of t4 4at5r1jwqithis field increase?

  16.47: Two small loops of wire are located close to a wire with conventionf)hy6z z5 .f5 vebq2nzrjg/0 2z wk4cfal current directed up the page. A scientist then moves the loops away from the current as shown. What is the orientation of zy04zr ceqf) w5 n.z5g6fzbj/ v2 2fhkthe conventional current in each loop while this occurs?

  17.35: A metal bar is moving to the left a/m 1)igvfiflh6j8*0x oad8vh3 x xw8ycross 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 thev8dy8 iwi 38j/x0*hxvgxaf)1lhf om 6 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 shgfzg,n68rqke*ust2v uct3uy/6 :.3s 4s xhio own. The magnetic field of the solenoidrno f *4skx yug3,su.s z he/6gvut2t8:qc63i, 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 thl:;xja 7vhqa3xlv /;jeti73+vt j n;le page is decreasing in time. A constant emf ξ is produced for the square loop enclosing the field in the filhv3lj/xi nta:7el v j;qv+t;7x;ja3gure. 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?