94.20: A magnet is dropped through a 6ia.zkiqz p9(ev 6p*xa97ijlvertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the ma.(x6 liaj6ezp 7pzqvk9ia* 9i gnet in the pipe falls:

  01.30: Lenz's law concerningq x:ma8w +nx5n the direction of an induced current in a conductor by a magnetic field could be a rest5:a x q+m8xwnnatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/secon8fd k/0kjpx 8o*nykfc a1q/ j*d) is equivalent to which one of t 1 /jfnjo*x0 /*pfc dk8qka8ykhe following?

  04.34: A square loop is placed in a uniform magnetic field perpendicular to zd)s2wuo lv t(wgi- 1-the plane of the loop as shown. The loop is 0.5 meters on a side and the magnetic field Bodvz2 u1- s()witw- gl 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 sa*tu/))u06v uyuw lv. The wire experiences an induced charge separation as shown. Which way iy)u /6wuavsl*u0vu )t s the wire moving?

  00.20: A wire moves with a velocito6 +2lhalmchws2nu;os z /lf./s(e z+y v through a magnetic field and experiences an induced charge separation as shown. What is the direction lh+f .a 6l/ /em(swl;22ohossc+uznz of the magnetic field?

  05.33: The figure below shows a bar moving t pwzs5ne0w(kc ,4cvqlyf57bq6 ;j ayd. (f/lxo 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 area contained within the conducting railsl qvcqw5p,(e fz0jx y5l f;cb/w4kdsy a76(.n?

  00.10: When a wire movid r8;v f taib zbw51))04ppxvvc4cgt-ng through a magnetic field has a voltage induced between the wire’s ends, vicvtpdvxb);8 - fc51pr44 gbaw0)zt 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 copp*i+dt,tx0n1+ f0c izj-bsr y xer rod has constant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are 1jynd*+i+ t -,xx0fct 0sibzr all mutually perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its opening isg;l4k sig3kzzc4, t0m perpendicular to the cirg4c;kslt3m g i,04kz zcuit 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 labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (which are assumed totd)z xlgtiad )skcr m(*b:844 be close to each other), the resistance of the left-8kg 4)t srmd i:ldc4b(z x)*tahand circuit is slowly increased. In which direction does the galvanometer needle in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet is held very close to the opening of a solk rq+j3 az5hg9enoid 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 andqj53gr haz+9k 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 7 ab4m9jlufry 9.x0h 5:cmdzton the left is increased at ahut5.bml79 0:zmjyc ad9 xfr4 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 held very close to the opening of a solenoid as s5gvv:rwt;lnk +tt3n: 5ojxv:how+k:v v r5vtt:35;lwon :jtx gnn 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 the “??” in the diagram represent?

  14.34: Two circular loops of resistin 1nnssx:6lv9 b9qh(y,b ;eidve wire are placed next to each other as in the figure. The cirq9 ;i:1 s nyv(ebnd9x,6lhn sbcular 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 shown, the variable resistance of k6zsi1q2e m /)8 gw+iyx,xj)q5h mrhkthe 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 resistancpppke 6to.t3 .cs 8b k+lg73xwe 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 to apl pkhi7 6j,(r spatially uniform magnetic field pointing into the pp(6 lh jrik,p7lane 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 conventioa rb 5s tkqx 36;sz+2d88vtpoqnal current directed up the page. A sca s;qzk8v3p+stot 2r5xbd8q 6ientist 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 movi si n,sdt3+i7ong to 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 cui+73t do si,snrrents through each resistor at the instant shown?

  08.50:. An infinitely loh u1zdizm0v(7ybwk 8;ng solenoid passes through the circuit as shown. The magnetic field of the solenoid, directed0 yvh8mdb zwzu7i (;1k 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 directeq2/ *s*j5/pmh+:us bcpsth y zd into the plane of the page is decreasing 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 through the center of the loop. What is the magnitude of the v*h2hyt +5 zs//sbjpm :su*p cqoltmeter’s reading?