94.20: A magnet is dropped throug 5vlatg0,1u) ttdf*mz h a vertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magnet in the pipe fall* uztgvft t5)l01 a,dms:

  01.30: Lenz's law concoq1e)hdc 3h/: d i9fk :frgxmjtj 1g,8erning the direction of an induced current in a conductor by a magnetic field coc/hff j19t jd:km1) o:r xqg3e,ihg8duld be a restatement of

  11.25: The product (3 Teslas) × (2 me*r h qcno1o3e8nbje.3arb4.fters) × (4 meters/second) is equivalent to which one of the rqb.o aj4hb18rnfe*.c3 3oen following?

  04.34: A square loop is placed gbjoz3ubri an(, a8+- 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 8uib(a- a+ob ,zg n3jr 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 img8cza ,x ;-1 hxfw7n8 apnhb0nto the page. The wire experience87h annfm ; p10gaxbxz8 -,hwcs an induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic ln 4 d o+9/gdklk,n2l obk3op 143fidofield and experiences an induced charge separation as shownkll/dd3pkod,4kf3 o2 l oon9b1 g 4+in. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on 16k m3bbgc2)y/wra im glv6p* two conducting rails. To make an induced current i in )kb ig r/ 6cwlmy1p a6b3*vg2mthe 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-vp 4k gf8crbb x;t15b a magnetic field has a voltage induced between the wire’s ends, thak 4 b1;xvbt8f5- rgpcbt 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 9z74 r hgmixmcii xuu/:32hqz3ht;k;0.30 m/s traveling through a unif4uh chg2ki;x;x 7i3 qimh3/ 9r:tz mzuorm magnetic field 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 perpendicula*5y,uz:tmr3 4 rsc attr 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. Acm , 435szr t:a*trutyssume 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 5j237zuip2vs bh0mhoare assumed to be close to each other), the resistance of the left-h msv0jhio z3pu7b52 2hand circuit is slowly 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 hel9dcm)c3da .8 h+g j6i4lysmpe d very close to the opening of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid at constant speed, what is the a9jdmes 8)m+.gc36 dcpihy l 4direction 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 crgln1 (b-g.cvcqu/ v+ ircuit on the left is increased at a constant rate. What is the direction of the magnetic field at the point P lbvn-cc (+1ggqrv/ .uat the center of the left-hand 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 ver6ec1dbggh;v/7n s pu+ y close to the opening of a solenoid as shown in the diagram. As th gp 1bdce/gv76 +;nshue 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 rk/l:g8g ; zls:sf8idoesistive wire are placed next to each other as in the figure. The circular looz kf sdos:lgl:i; g/88p 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 th( /-lgp jn6 kic9kfv5he 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 in*uo;hl v n; p9.zyf)punercircuit $R_{inner}$ 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 wirlru1p6 uk)iw1e loop sits in a plane perpendicular to a spatially uniform magneticluui1 6 1wp)kr 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 this field increase?

  16.47: Two small loops of wire are located close to a wire with co qszdugf;7- fh48va*mnventional current directed up the page. A scientist then moves the loops away from the current as shown. What is the oriz gud*q7s4a;mh8f -v fentation of the conventional current in each loop while this occurs?

  17.35: A metal bar is mo 6jcu9qgz1 if*ving to the left 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 idenjg*cz 9uq 16iftical. 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 g ..r7k9xa(:/a ch7v adcrkb.bkq av,as shown. The magnetic field of the solenoid, directed intokaa..x7 7 k/c(d k cbvqr.bvgrha:a9 , 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 is decreamimx g r- dp6q8wl;l)b3 f8c1lsing 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 resistan c p6)ld1 ml8xg3imwq;b-8lrfce 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?