94.20: A magnet is dropped through a vertical copper pipeow6p z52dzhz*m*mzj.7r* zun slightly larger than the magnet. Relative to the speed it would fall in air, the magnet in the pipe famnz5*6o zdz rhm.7*2pzu zwj*lls:

  01.30: Lenz's law concerning the direction of 0.g/+uhlzar/eocgw i,w8 t f0y8 dm (ean induced current in a conductor by a magnetic field could gri,fyad0eo wm0tz8w.gl8+/ (ceu h/be a restatement of

  11.25: The product (3 Tesl)(drku8 *b jzaas) × (2 meters) × (4 meters/second) is equivalent to which one of the8 j*durzab) k( following?

  04.34: A square loop is place g5+;zm/0 hz.wd kob-s3lxztc)lo -kdd in a uniform magnetic field perpendicular to the plane of the loop as sho 5o0-w.g/ t- k mo)lzdl3+hbzczsk;xdwn. The loop is 0.5 meters on a side and the magnetic 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 thrt 3l8obzqp,;;v +gquzough a magnetic field directed into the page. The wire experiences an induced charge separation as sg+v3ou,; btqzzq8 ;plhown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetif7pgs z+0dks. c field and experiences an induced charge separation as shown. What is the direction of t.sf+ dz0sg7k phe magnetic field?

  05.33: The figure below shows a qnlx3 6r5z0lb1 6,8cjs vzbnibar moving to the right on two conducting rails. To mcr 3j6v5bz 68s ,1qin b0zlxnlake an induced current 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 moving through a magnetic field has l3/e 6- jp) ku)lq2(pdurmarp a voltage induced between the wireqedpuj3r ml u)2/kar -(ppl)6’s ends, 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 hq))-11i vcu j:u lj*rtylfto: as constant velocity 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 difference induced across q:1f)jitol *)-ulyr: v1cut jthe rod’s length?

  04.42: A solenoid is oriented end-on so thaah9r.9p/4 ) 2fqe6aqy ckwpilt its opening is 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 pa.4 yrpqp)cq9fkil 9hw6e2/a lane 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 (whichsa b*tb4 jkrtlj 25kjy6+,el0 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 response to this ch25, lbljtb+t0yra6 kjjk4es *ange?

  08.29: A strong bar magnet is held very close to the 4;e srwdqzqal )0iy6/opening of a solenoid 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 and what is the direction of the forcz d lwes;6r/aqi04qy)e on the magnet because of the induced current?

  09.37: For the figure shown, the varia ax:+ d(ob57v8 jis +yhxcnyt *arnj:.ble 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 yt8djo :s *+ njacany5bvh .x+7: xir( circuit and in what direction is the conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnnx ukfti6x:y9,+ t6l bet is 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 ,k bt 6 ultxxf:+n96iyconventional 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 rj jw1t)g 8fnref5 ts5j5d2 ;2glpc:f qesistive 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 lewer tg25 qgf 25jjj;pdcfs1f)tl5:8nft-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 the outer*nshl9g29 dk 0 peew0f 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,j z8zdu*o c*;s the variable resistance 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 perr(yf nav7vrtq2h +yk 7 j5.ry,pendicular 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 followin(yjy.rhrvy25t 7vq+r na7 fk ,g effects best describes the result of this field increase?

  16.47: Two small loops of wire arexufvi8(ok-8j94 cy 0a le1bfcdk /w*v 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 (/fu lo-c *ajcv8 4wk d901eyf8xvikbof the conventional current in each loop while this occurs?

  17.35: A metal bar is moving to the l63) 7ibyjvclyqda(t)n3q a m1bw 3ljrci ; ,y)eft 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 currents throughibm ;)j31yb)qyc dl( w ,tyj6vclr3)a n3a7 qi each resistor at the instant shown?

  08.50:. An infinitely long solenoid passes through the circuit as shown. The m*3yww5 rsteu) agnetic field of the solenoid, dirtw 5y*rswe) u3ected 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 plane of the page io- . ejj9 q)clap;:zsxs decreasing in time. A constant emf ξ is produced for the square loop enclosing the field in the figure. The square loop has three ide:.q)c 9-szxpl; o ejajntical 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 voltmeter’s reading?