94.20: A magnet is dro 1,x5wd 5zomdopped through a vertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the wd5oozxd1, 5 mmagnet in the pipe falls:

  01.30: Lenz's law concerning the direhgx ek1ncyu2,n. a/s)ction of an induced current in a conductor by a magnetic fieldy2./gnhsx )e cu1n ,ak could be a restatement of

  11.25: The product (3 Tessy 5/jfmodo0z 5 2ty/r6abv1 elas) × (2 meters) × (4 meters/second) is equivalent to which one of the follo 5/ot5bdyof2vsje r 0/zym1a6wing?

  04.34: A square loop is placed in a uniform ,6zxa4l+ 1m + enjuafw 5-huabf,y;qbmagnetic field perpendicular to the plane of the loop as shown. The loop is 0.5 meters on a yabul,m46z faf,; eunwxh- +5q1ab +jside 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 0( 1o.vyslup w 1s6xftthe page. The wire experiences an induced charge separation as shown. Wh60px.s1ly1uw ft(sv o ich way is the wire moving?

  00.20: A wire moves with a veloc3/lrkuw-tkp 8i x;5+u4zckgo ity v through a magnetic field and experiences an induced charge separation as shown. What is the direction of the magnetic fie/ w45 ui38co kt+z;gkpulkrx-ld?

  05.33: The figure below showuhy o3f- kn1h.s a bar moving to the right on two conducting rails. To make an induced current i in the direction indicated, in what directiohkyf.o3 -h n1un 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 induced b93x0u9x/ci7m1 ;gsiuuf* 3qle krr 4 agr3 iaaetween the wire’s ends, that voltage iag gqrxr*eusfk49317i3m aui9l a;/i0cxr 3us
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 ebj)70mwi7uw.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field 7b0wu )jm7wie 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 per 3 aov ey*zat9kvouov;y(zdp (yz;yp2hh0,.5pendicular to the circuit containing the two light bulbs as drawn in figureyez2ydvyhat09o ;o ,k vvo(a.up hzy3*(5 ;zp 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 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 arei5z71n3-(ho( 0kj5jn fi zlnes3cajy assumed to be close to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galvanometer needle s( (fna zcy hjj7i55 0ozji3ln-3n ke1in 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 sh5vl1bn k-8u l; zqkzh(cqp63 cown in the diagram. 8k( zn q bc3vl56l-ucq;h1pzk 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 shown, the variable resistancb2 k*ic)ssrn.a.x* l,g+ it uxe 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 cis .g )+2a*ix. nr tucl*ks,bxircuit and in what direction is the conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is0th c3,du;r(j5rv lua 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 conventional current throu3 ,lrh;d ac0rvjut(5ugh 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 resistive wire are placed nextb ;5qhni p*ih3 to each other as in the figure. The circular loop on tb;i ih n5h*3qphe 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 outer circuisfn 8fecnig :s.)kee ((gu( g+t $R_{inner}$ 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 ry6 l/dj 3 .tox/)cmodyesistance 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 perpendicul+0it pth7 1rv0go(a9j nxx 1lpar 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 best describes the result of this field increaso+a7j9 tlx0vt ph1r1 n0pxgi( e?

  16.47: Two small loops of wire are located close to a wire yoz2y erzagb+h 0z)pc06+-xr 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 each loop while+x pzo6y)0rb0ay2 hc -+zgzre this occurs?

  17.35: A metal bar is moving to the left across a set of fr0mja5jld/ ag)g a7s4eictionless conducting rails a j 5a/4 jgeda)gal0sm7s 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 ae7n77a 7deur as shown. The magneen7ur7ea d 7a7tic 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 fieldf:j9:75/v pj+ )slhgt grgep3se oyn 7 directed into the 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 bulbs of resistance R in it and an ideal voltmeter connected to the corners through the center of the loop. What is the)pe 5ynjh+ :7j:s/sl9vptg7o g 3efrg magnitude of the voltmeter’s reading?