94.20: A magnet is dropped through a vertical copper pipe be.d ty.1xvzs3 n;6i xslightly larger than the magnet. Relatib 1ns.6zd;te .x3yvxive to the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the directioxbawc1)xx;d+;n 6 xcp at.m7kn of an induced current in a conductor by a magnetic field could be a res6t)7mnx. a dp abcx+xk1cwx;;tatement of

  11.25: The product (3 Teslas) × (2 meters) ×hpdm jj k*27pt,nwr); (4 meters/second) is equivalent to which one oftd2rj;nm)w7 kpj,* h p the following?

  04.34: A square loop is placed -l+3iw d hn0fxin a uniform magnetic 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 of 2 T. If the loop isl0h-+ w3nd fix 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 intfth:0-;mh2bbfxtf l3 yav-5v tyb0 +yo the page. The wire experiences an induced charge separation as shown. Which way is the wire movif2-yb :t h;b0 fhb+atvym3vyl f-05 xtng?

  00.20: A wire moves with a velocity v through a l-u skvw)w -/y,,ezj:bpnit+magnetic field and experiences an induclu e,s- ,+w-zk vitjbw/y:)pn ed charge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on two conducting rails(c(i xb a2,oetofip+2 kko3o9. To make an induced current i in the direction indicated, in what direction would the magnetic field be in the area contained wi3o2o(2,tixcok(ief kpoab +9thin the conducting rails?

  00.10: When a wire moving thr kusjm8,x-rxh:cn .-vm 14 pxpough a magnetic field has a voltage induced between the wire’s ends, that --. xk4hx, pmrnu1cpvx :msj8voltage 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 trjgkq 3kwib6d 0h, r) cw+.gk)maveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the poteq 30m+, g6wkg)cwbhdr.)kikj ntial difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its opening isyq nf.:nb7pd/ q;dw p( 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 of the bulb labeled R1 from brightest to dimm : d/wq7;nbyn(. qdfppest.

  07.34 For the solenoids shown in the diagram (which areddidv 6m :q2sf0b3r.w zp/ si7tu15rn 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 thedrdz1 bq/v i 27m:.p6i3r5sdwus 0n tf right-hand circuit move in response to this change?

  08.29: A strong bar magnet is held very close to the opening of a s+vhmu9sd508 f7pm7x ubte 1hvolenoid as shown in the diagram. As the magnet is moved away from the solenoid at constant speed, what is the direction of conventional current th7fv ht 1+90pu 8m7mxbv 5eudshrough 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 on the left x/nn( of 2z,fj/baag- 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 andx / ajb a(2fnzof,g-/n in what direction is the conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet i tm z:s;)8 sn4vdbimr+s held very 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 +m4:nz )vmdi;s8trbs 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 resistive wire are placed n;tvd8 s0 mei xz)mih2rch*:v7ext 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 rd x*80mzmce:tvih 2;ivhs 7) 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 3y/iidaoi*+e0 2 oajkresistance 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 innercirc1x,rvj zw n3qwpid+62pog :.fuit $R_{inner}$ 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 perpendwy 0r* t;uqsx3 2zz5hcicular 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 y0zc;xuz2 wshtrq *53 the result of this field increase?

  16.47: Two small loops of wire are located close to a wire with conventional cnva2 i vf-di7hx;fys 0cx*98h urrent directed up the page. A scientist then moves the loops away from the current as shown. What is the orientation of the conventional current9 ;hy8c -72n axifsdv0 i*fxvh in each loop while this occurs?

  17.35: A metal bar is *jzas-om2nx; diq 0+ tmoving 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 co2;*dxi0 jn-m+ast zqorrectly 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 infinitely long solenoid passes througsr3sdx6cg v*:; o(hc *h ajbj5h the circuit as shown. The magnetic field of theh (*hdo:;a s*bcjsvg3r5 jcx6 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 p8dw50vge4onewr6 k)n lane 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 through8 r)o6n ve4we5gdk0wn the center of the loop. What is the magnitude of the voltmeter’s reading?