94.20: A magnet is dropped through a vertical copper pipe slightly larger th-+fnh( lj2e2 /o qqkxoan the magnet. Relative to the speed it would fall in air, the m o22(n-ekh/+lojxq fqagnet in the pipe falls:

  01.30: Lenz's law concerning the directionwq uzj6igx* a3x2 2h) t-st8jt of an induced current in a conductor by a magnett)x i6x - jtwuq h*38s2jz2tagic field could be a restatement of

  11.25: The product (3 Tesl7hpj 4vzq0/omas) × (2 meters) × (4 meters/second) is equivalent to which ovj04phq7 m/z one of the following?

  04.34: A square loop is placed in a uniform magnetic field perpendicular tz(co9y zekw ,7sq.fk0)i-tmk o the plane of the loop as shown. The loop is 0.5 meters on a side and the m ck7fok zwizs0.y,em-9qt (k)agnetic 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 fq /znoax. z2gvwlxf 0( :9a+vinto the page. The wire experiences an induced charge zx qgvva9w :. f0f(zx2/l+a onseparation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity .+ -cmijh(fm.yk+6rqcvlcz3f c ql* / v through a magnetic field and experiences an induced charge separa 6mcf k+ i3z.f. lmv(lcjq*rh+-/ ycqction as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right onxvb swpc8y)as:sr*z ;g jed.+j1z t08 two conducting rails. To make an induced cg0cj:jtyzb 8 sx1.z ;8wep+ as)srd*vurrent 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 movizpn0n--ilkd 491p.iid vbz0 eng through a magnetic field has a voltage induced between the wire’s ends, thatl-e n0div-0 91.niiz p pbz4dk 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 through5qvik kyq)g(6pa za r1(ae6c8 a uniform magnetic field zvyic 1rpk8a)qa 6(gq5ake(6 of 0.060 T. The rod, velocity, and magnetic field are 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 is perpce4iwga bj,9//1s w+ef: ex pjendicular 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 pag +esxb ec1w9e pi/jg,4/jw:fa e, 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 show: nc8 5aba *v-dqpjk7gn 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 circuit move in rjkna8*7acp b5- q :vdgesponse to this change?

  08.29: A strong bar magnet i ,p71 o2rzvvgqwg u1.ss held very close to the opening of a solenoid as shown in the diagram. As the magnet is movedrv.2o1 p z,vw7u 1sqgg away from the solenoid 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 resistance in the circuz 08et0z lup(x c))h*xh och2kit 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-haxccok* t2 zh)p z8)hul0hxe0(nd 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 shsr+js e- -w7 si6-xr t;p 21qn29mgjreg(ljqolenoid as shown in 6whexsjti j-2qegl19+rm - ;rsg srn-j7q2p( 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 resistive wire )q,a/n5le;fq5n dajv 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 v /l5)naqj e; 5,naqdfis 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 hokd+y . ;,:wh*gzi*,xilbenshown, 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 resistance of the innercir q3azzbb3(xv+cuit $R_{inner}$ 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 perpendicg,bjfso 8eg o pj*)74aeada3j upk1;6ular 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 th u*g8jbj,1f )4osepa3dap7 a ;6kj ogeis field increase?

  16.47: Two small loops of wirei9vgq: a1nl b9 are located close to a wire with conventional current directed up the page. A scientist then moves the loops away from the current as shown. 9lai:vnbqg1 9 What is the orientation of the conventional current in each loop while this occurs?

  17.35: A metal bar is moving to the left acrossoxtm b4w8f6ig9vf)n, a set of frictionless conducting rails as seen in the figure. Throughout the region between the rails, there is a uniform magnetic field directed intoftgm8o),9x 6w4 nbfi v 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 instant shown?

  08.50:. An infinitely long solenoid passes thg,p g j)s- bbv0ii58 2+ffecumrough the circuit as shown. The magnetic field of the solenoid, directeg jgbi8 2mbecfi-50us)p+vf , d 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 in6(6 t4hgmfuo fto 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 voltgh6t64mf o( ufmeter connected to the corners through the center of the loop. What is the magnitude of the voltmeter’s reading?