94.20: A magnet is dropped through a verti4p(abpfbq a/c d 76f8h*vpr. pcal copper pipe slightly larger than the magnet. Relative to thedpa fp8v.a cprf 46bhb7p*/q( speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the dirkpmbqs q(- b9rw qm9.g(a39 xfection of an induced current in a conductor by a magnetic fielx( 9wpqkr .-3a (9smqgbfmq9bd could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 mete kts/ax ow +10qh)hl+yrs/second) is equivalent to which one of th)/+a 0ho ts+lyhxqk1 we following?

  04.34: A square loop is placed in a uniform magnetic field perpendicular toes4n87i-7e yd3bktg k( ;wgdd the plane of the loop as shown. The loop is 0.5 meters on a side and the magnetic field B has37dy; dk4 ne g(wskgibedt87- 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 magnu 9kjii zc9+7p8oze 4zca8yt ,etic field directed into the page. The wire experiences an induced charge separation as shown. Which way is the wirck7j48+9eziu , oti9z zcap8ye moving?

  00.20: A wire moves with a velocity v through a magnetic field and exper0e.ca29vn(yp h w b*guiences an induced charge separation as shown. What is the direction of the magneticch2w.*vug(y0nba9pe field?

  05.33: The figure below shows a bar moving to the right on two co.*k)x)am1ytdok4b pq zquu0 o 5,rh7v nducting rails. To make an induced current i in the direction indicated, in what direction would the mabk oy* rp7 q5tuz0o m hukvx)da1.,q4)gnetic field be in the area contained within the conducting rails?

  00.10: When a wire m:qs yjg/n97ua2i-idroving through a magnetic field has a voltage induced between the wire’s a/ duirqs-2 7j9ig:ynends, 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 vel:s t(bn nlzx):ocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potential:(:z nlnbt) xs difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its opening is perpendicular to them-xlp(7p9 :srrpwwo: qor ;0+y8ru xg circuit containing t:w p;mx0rr:s w7q g +prp(olyr8-9x ouhe 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 solenoidu;g;em 7d7qb*iv lgx6pm( q j.s shown in the diagram (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 in the right-hand qe. gd p6m7qvx7 j ;l(gmb*ui;circuit move in response to this change?

  08.29: A strong bar magnet is hy b s x*l+hzy-8:r5; mhcjp;rceld very close to the opening of a solenoid as shown in the diagram. As the magnet is moved away from the soc;5 p* s8r r hljybxmc+z;hy:-lenoid 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 resistaasb l 000+ quvfsz n-j2n *kjpid.d04bnce in the circuit on the left is increased at a constant rate. What is the direction of the magnetic b d f 02p0s-uqavl.j+0skz n40 ndb*ijfield 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 2w 5g d* p 6mnddafeb4;1ad3ecclose to the opening of a solenoid as shown in the diagram. As the magnet is moved to the left toward the solea4b3* nedc5wd g1a ;p2d emd6fnoid, 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 re,rfsz/ r /ag9 wb.kt)wsistive 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 field at point P (the center of the left-hand loop) and what is the orientation of the conventional current in the right-hand l9s bw.rw/ak,f)rztg /oop (as viewed in the figure from above)?

  11.41: For the figure shown, the variable (fxsjf9 r.6byorlan pm7sk9a w2:- h(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 resistance of the innercircuitcw83vj * tsjik6: tr-o $R_{inner}$ 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 looupw tmz26 )x0gp 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 fou0zw2pm6)tg xllowing effects best describes the result of this field increase?

  16.47: Two small loops of wire are located close tf26b+zdmj4tfe)7+gwo z xw-f o 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 wjd et7g o fxbm+f-w2zz64)+f loop while this occurs?

  17.35: A metal bar is moving to the left across a set of frictionless cyy1i2vu m*,nt onducting 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 resistor at the in,t21mn*yviyu stant shown?

  08.50:. An infinitely no2sx2,pzl dxm6 q,i0+io2 julong solenoid passes through the circuit as shown. The magnetic field of the solenoid, directed in s x,q6 l2odo+2mjp,u0i n2xzito 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 1 bnfqz*a-pkx- dxmg2+hu)qj9* t(ujb5hn,d 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 cente)-huq*k dgjamxx9hfbnu-b(15 d t nq2jz+,* pr of the loop. What is the magnitude of the voltmeter’s reading?