94.20: A magnet is dropped throvm/(bm nj ;tu b8r2/beugh a vertical copper pipe slightly larger than the magnet. Relative nb bvrjb/ ;8u/tm2(em to the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning thx99q/c b.pwpef r, cs6e direction of an induced current in a conductor by a magnetic fieldpfr,./qcw xs9bc 96ep could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is e2loy3ifou06 j quivalent to which one of the follofo02lj u y6i3owing?

  04.34: A square loop is placed in a uniform maoq6s:ng:d, ct pef(u7 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: 7qsnpc ft gueo6(,d: 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 dirl lg,/hi30b+g7 caiy t 8-ijxuected into the page. The wire experiences ani/hci7g -j,gl a 0lx+b 8t3uiy induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and experiencesgps3ws ,0kl2klt/cy - an induced charge separation as shown. What is the direction of ts3l skl-pw2c tky,0g /he magnetic field?

  05.33: The figure below shows a bar m2 b),1 fzsi tge(:rtbwoving to the right on two conducting railstbgt1w()2be srf: z, i. To make 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)/wgllcrs xg(i )d:s : a magnetic field has a voltage induced between the wire’s en)lgw :l /cr:(xigdss)ds, 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 thr2f0t1ikz c82hq) xah 9e,pnxgough a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potential difference induced across theeh pzxa2)91t02 gkncf,xh8iq rod’s length?

  04.42: A solenoid is oriented end-on so that its opening h 6bwp;t6v0x z4v0bi2yja5d j6hc ijc)8cd g* 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 plan6cc b jvibx ;6z6 h028d4htcdviwp* yj0 a5gj)e 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 diagra7fixdmk pb )2k n-;51m/ntvr mm (which are assumed to be close to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galvanometer needle ink;mvrmf2x1bnm)-dkn 7i p /5t the right-hand circuit move in response to this change?

  08.29: A strong bar ef .xwtt /3ph+magnet 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 thx + eptw.ft3h/rough 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 v fc0u.ovm11 gwsnzw..4ts8 kaariable 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 dir .fw stg41.c8w s1mvku.ano0zection is the conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is held vs lu6+;0r eenulopz69ery 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 sp+ nleru;us06 lz6eo9olenoid and which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of resistive wire are placed next to ea6hagd +vxnl* d06uydzx)k36ach other as in the figure. The circda*dk6uz hy vx dlxnga6630 +)ular 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 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 sho *ont ,ob7t:pbwn, the variable resistance 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 resistn 3ohq4)pphr0 ance 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 perpendicular toqdz3a-r,tnr sx,h-vi8z :):e c nxl0h a spatially uniform magnetic field pointing into thn e nq : xitz0a,rsdl cvh:--38)rh,zxe 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 close to a wire with conventionftvemtp2x( h+hni+q+.ql:1 q al current directed up the page. A scientist then moves the loops away from the current as shown. What is the orientation of the coq+( xnv1heqt+:lf2impq +h .tnventional current in each loop while this occurs?

  17.35: A metal bar is moving to the left across a set of frictiont .lvus,np(g6d mt 7;kpv jx5orcv02,less 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.vpvxl r6,tp2j,dc .s0 (knm5v u ;gt7o 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 infinitel1 7ifxo fcr9c+y long solenoid passes through the circuit as shown. The magnetic field oo cc 1fx9r+f7if 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 decreasing)b+iw7k r zaedri dz52+t+b(m in time. A constant emf ξ is 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 tm+db7i2+5zirwbk(et zdr ) a+hrough the center of the loop. What is the magnitude of the voltmeter’s reading?