94.20: A magnet is dropped through a vp.ih*ni )d-ggy ) 6auyqy jj3t3,)fqw ertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magnet in the *h)gt)y-.pynu 6q3af)j iyq gi, w3jd pipe falls:

  01.30: Lenz's law concerning 7ei5 3p0l8w ehp;lkbaltalg1k g3*8e the direction of an induced current in a conductor by ak371li*83lbep a5we; gtp 0lg lahke8 magnetic field could be a restatement of

  11.25: The product (vsa0b* m)qvf8h; wu-a x,cmi43 Teslas) × (2 meters) × (4 meters/second) is equivalent to which afm04wqih cv)- bv;su xa,m*8one of the following?

  04.34: A square loop is pl; i-8a6(z;gv-vucz ipbzm(, z-zzsk l aced in 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 guvz zkz-z,svc;zip6bi;-a8 l ( -m(z 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 through6huc- dlhdl1 c*9h1gn a magnetic field directed into the page. The wire experiences an induced chargcudch*ndg196 -h ll h1e separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and e)g2p9coy -d ujxperiences an induced charge c2 u)j9y-pgdoseparation as shown. What is the direction of the magnetic field?

  05.33: The figure bew+3r9bfoytjk zbi8a /r-44 xf low shows a bar moving to 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 wi/k -bb4jia 3xwo9ff48yr t+z rthin the conducting rails?

  00.10: When a wire moving through a magnetic fky y 20(4i2;x,ahd-xtr8up mcme t1n xield has a voltage induced between the wire’s ends,x4kt2 cxn-0(mdt2h r y8xm 1pia;ey, u 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 trav+0lwl-rmm k. o:kd,ose a-:vb eling through a uniform magnetic field of:-,.bo+ws lk omkar:-0l vdem 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 idb3+h8rslwqvpm hq9d/ssizp -87 7 s2s 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 thdsh8s9+zq/ s-72wdvqrp 3p 7mhi bsl8e 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 as krw7oaq/;m;z e24fonw)z5 sfsumed to be close to each other), the resistance of the left-hand circuit is slowlyzkea 4/qwznwofom )7s;5 f;r 2 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 solenoidy y7wgv3q*d dfp9aoc0 ,mu6-d as shown in the diagrwy0f* 3-gcypda6m9,oqu v7 ddam. As the magnet is moved 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 showx5nm.k d07agf hllpufk h2*/;n, the variable 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 whatx7 pf5 hhlf;0ukm lak*dng.2/ direction is the conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is held very close toc,eyxvt4/8:u nk/ bmo the opening of a solenoid as shownt/me/x4ou, :y kvnc b8 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 resiswj:f:e.pai9ujf c f/0 tive wire are placed next to each other as in the figure. The circular loop on the left is connc:uff /e9a : .ijpfj0wected 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 variableo-p7g+euoi;y;jn 3 p i 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 re/p vc4gok0qvud+ i+-csistance 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 /- w-ajsv+-pm er +bsae n)gl-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 following effects b+r /vwa-+ sb-epa j -n)slegm-est describes the result of this field increase?

  16.47: Two small loops of wiid g h*0kqwyb3,y;dt(re 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. What is the orientation of the conventional current in eg3 0 d*kdy bht;yqi,w(ach loop while this occurs?

  17.35: A metal bar is moving to the left across lg0, rstz2zzyq 5x-p, 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 indicax2l-zt y0z,qrg,5zpstes 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 pj* 4drb(q d5fsolenoid passes through the circuit as shown. The magnetic field of the*r (jbdq4dp 5f 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 planev :8m.*vffp8(* einph cc vx5w 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 cen*mf:ev(5ip v .fcv*w p8nh8xcter of the loop. What is the magnitude of the voltmeter’s reading?