94.20: A magnet is dropped through a vertical cop4x 99-5lwd; mwtm4cmd* msov/z9hz ryper pipe slightly larger than the magnet. Rew *tw/zs 4dczyxdv mhml; 5-o 9m49m9rlative to the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concefle7mab::j e6 rning the direction of an induced current in a conductor by a magj fema76:e:bl netic field could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 me z( mzgz799aotn1n8frcc6a5dvy3gc 1ters/second) is equivalent to which oy 8zdcno719czavg n195 z(t6m cf3ar gne of the following?

  04.34: A square loop is placed in a uniform magnevtb;p /c5-zq w 14kjmntic field perpendicular to the plane of the loop as shown. The loop is 0.5 meters on4;j5 c/1wkpvq tzn-mb 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 through a magnetic field directed into the page. The wiw yih-ji*39a v xm7 xjzx+n72ire experiences an induced charge separation as shown. Which way is the wire mnvi3j xz iixy+x -wm79hj27a* oving?

  00.20: A wire moves with a go )9a zzz7l vb3wc(,ap.,zc+ya gi2qvelocity v through a magnetic field and experiences an induced charge sepa 3li.go,qg+z 9vb7 zc), yaapzw(2azcration as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a ba7 ,mu7fqu :bu iinc1w2r moving to the right on two conducting rails. To make an induced current i in the direction qfu2iun17 umwb7c:i , 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 a voltage indusmbk::pv/jj3gvjew x:4 4nl0ced between the wire’s e w4nbs0g jmv3el4/vpxk :::jjnds, 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 traveling througzf ekn6g8n. 9ew *j(sn xlt+s6h 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 the r*ejs f z96 ln8n+ .ge6wtnxsk(od’s length?

  04.42: A solenoid is oriented end-on so that its opening is perp8dmyv6:v nzkks/ 40guendicular to the circuit containing the two light bulbs as drawn in figure C1. For figures C2 and C3, a shortin/ kg4 vkmz6d8syn:u0 vg 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 solenoids shown in the diagram (which are assumed to be 58fpv(ez w / u1-izs fsxn0(aoclose 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(xu /fpe0 -1s 8z(na o5fvwizs change?

  08.29: A strong bar magnet is held very xr c 8+.hztnkx(gl b*q(,w2ebclose to the opening of a solenoid as shown in the diagram. As the magnet is mon*x2z8bhrb,gl wt( ck .xeq( +ved 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 figurekhae 7qxw ra:600c2m n shown, 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 what direction06ena7hrcm 2 a:kwqx0 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 solen;0z+yv -l 5adfpq 5il3jromh +oid 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 magnet because of the induced current in the solenoid and which magnetic pole do-0;qdl j yiav5mr5lhpz+ 3fo +es the “??” in the diagram represent?

  14.34: Two circular loops of resistive wire are placl1rwfc ./vf)v bm6m/zok gi61ed next to each other as in the ffrvil/ wf.c/k)6mv1m zb61 goigure. 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 loop (as viewed in the figure from above)?

  11.41: For the figure shown, the variable resistance of the outert0(pnub0ss mwp,/ qjv1 ajefh3qv z+ju1i5*4 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 variablwl)zl dsquv32ryo 0f3/s ef* *e 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 p8cq j;eg:t jc (u;g3ypg4go2 nerpendicular to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strength steadily increases with time. Which ugj ;4coyt 8n :e23c;qg(g jgpone of the following effects best describes the result of this field increase?

  16.47: Two small loops of wire are located close to a wire with con i+pe71w ,xgak)ur: p)-tbctfventional current directed up the page. A scientist then moves the loops away from the current as shown. What is the orientation offpa1tgx+: uc r))- ,ekwp 7tbi the conventional current in each loop while this occurs?

  17.35: A metal bar is moving to the left across a set of frictionless c-d/h* wg((nr1fj i +*y kpfw9m -dsfzlonducting rais fhrf-(jwd(g-d fwp iz*+m n*ly91/kls 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 instant shown?

  08.50:. An infinitely long solenoid passes through the circuit e(lb+n z6/9w8w;wcxrpo;l h e as shown. The magnetic field of the (lw; o hxc 6/bewn lzw9pr+e;8solenoid, 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 x qs;)rjg /xq,directed into the plane of the page is decreasing in time. A constant emf ξ is produced for the square loop enclosing the field ,xqsjg ) r/;qxin 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 center of the loop. What is the magnitude of the voltmeter’s reading?