94.20: A magnet is dropped through a dls3/co b c)l;vertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magnet in the pipe fallssbo)/llcd3c ;:

  01.30: Lenz's law concerning the direc4k;9pe n(1l xd f*qraztion of an induced current in a conductor by a magnetic field could be a restatemef (zxrp; qk1*4da9lennt of

  11.25: The product (3 Teslas) × ( u1sa7fgiwn-+ai4r4grd :, s: eei (rt2 meters) × (4 meters/second) is equivalent to which one of the fs44 ti g ara:u+i,i7ewf (r1drs:-negollowing?

  04.34: A square loop is placed in a uniform magnetic field perpendicular to4snc/v*gxz /z the plane of the loop as shown. The loop is 0.5 meters on a side and the magnetic field B has a st/ * /gzvcs4nzxrength 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 t 6inpvg1 va)/lvx44 yfield directed into the page. The wire experiences an ivnivg 64t1lv )x /py4anduced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a veloc4s* ss ef2utv.ity v through a magnetic field and experiences an induced charge separation as shown. What is th4 s*stufsv.e 2e direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on t5lig ef 9c2rq 3bbo5:ewo conducting rails. To make an induced current i in the direction indicated, in what direction would the magnetic field be in the area contained within the conducting 2bl 3o5cqgfi9: eeb5 rrails?

  00.10: When a wire moving through a magnetic field has a voltage indl vt49 g+7gixonpi7hsy0 : np.uced between the wire’s ends, that ot.g4n:x+09spi vih pl7g n7yvoltage 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 constantwv8 k+grjx) q:nmi2,e 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 potentia2,x+n ejk mig)w8q :vrl difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on sok v5b;+( wxbyu that its opening is perpendicular to the circuit containing the two light bulbs as drawn in figure C1. For figures C2 and C3, a shorx5w+;k( vbyub ting 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 ay(r+czwc-oyj2dm p-px mp6.a 5:i(a 99 wy znclose to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galopja9cwpi2-y :yd6myx +z(9a m-p a.r5wc(znvanometer 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 solenoid as sqb+7yza/j srv w6-d 9bhown in the diagram. As the magnet is moved away fra9dr67-sqw+j ybb z/vom 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;7z* ;;i aqx ft5)ux(yrmvb ac 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 direction is the cony;vxzb;t7 ) 5aic f(m*qua ;xrventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is held verds 3wg*x: v;pth1g ,*4vet44rkx 9-qnrfgeedy close to the opening of a solenoid as shown in the diagram. As the magnet is moved to the left towarx:xt4fk-v3qr4 r* 9evw d 1dg4*n,eetghp ;sgd 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 resistix+psj,,y 1ryd5; m unove 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 left-hand loop) and what is m+s1pd;,5 ou,nyr j yxthe orientation of the conventional current in the right-hand loop (as viewed in the figure from above)?

  11.41: For the figure shsyx 6fuais 7 , +z- hb003iyen+rdbvt3own, 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 innercirch +b-/mpz :;.c vv-+lunhqiocuit $R_{inner}$ 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 silszir:hkjk ) 48 p) ;i:u3atsits in 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 8;ips:u)3ihlzs r:jk k it)a4 one 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 conv ya.xy39 o)rfdentional 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 each looxay9 d)3 rfoy.p while this occurs?

  17.35: A metal bar is moving to the left across a set of frictionle77/f, ,-uh1 gk mdqhbggmz;oyss conducting rails as seen in the figure. Throughout the region between the rails, there is a uniform magnetic field directdgzf, q;g7uy,h mm- khb7g1/ oed 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 thm ra;a1; b2rilrough the circuit as shown. The magl 1aibr 2ar;;mnetic field of the 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 thejidd t,m78rtm3es0fm 7 u )du) 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 bul idd7)7fms)udu0tt 8m3j ,er mbs 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?