94.20: A magnet is dropped through a vertical copper pipe slightly larv 05v.sw(bpst av2,k;pv89m (msjh hbger than the magnet. Relaw209mb ptsmj(kshh;,v5 . p(vv8 vbas tive to the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerj*(7 ijb v;eqpning the direction of an induced current in a conductor by a magnetic field could be a restatement jibj p;e7*v(q of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) isexuss :re0xl n328qloq*cd:ii 4 /ud 4 equivalent to wx3q*sln e84c4/ eq:ri2 0osu i:ddx ulhich one of the following?

  04.34: A square loop is placed in a uniform magnetic field perpendicular *:zp8piaq:r do 2 4,gnec c4uzto the plane of the loop as shown. The loop is 0.5 meters on a side and the magneqd:g zcizr2c*:u p,o4 4nea p8tic 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 throug0hu1 +o4 hxzeqh a magnetic field directed into the page. The wire experiences an induced qe1 4hzho+x0u charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity 70jxzx9*vtcvv through a magnetic field and experiences an induced charge separation as shown. What is the ditxc 90vxv 7*zjrection of the magnetic field?

  05.33: The figure below shows a bar moving to the rb uf.v(cgc; 6j5a3mfi ight on two conducting rails. To make an induced current i in the direction indicated, in what dira5micf gcf6 3 vbj;.u(ection would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field hagh,co /hs va-+kjh 6+as a voltage induced between the 6-hc,ash +hjovkag+/wire’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 coppevhz7h v34 e/ ieyoxkxrk 8f84.r rod has 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 isv8z xh7xv3y8 ke4io./fh4 erk the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so t oh8htzy0l fguu) 0 c.6fv0d5jhat its opening is perpendicular to the circuit containing the two light bulbs as drawn in figure C1. For fi0 dvh8 o)5 ugju0f fylt0.z6chgures 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 are 7 uwb5rg2:d kfny7s; zassumed to be close to each o5g kdr7 w; u:2ysfnb7zther), 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 change?

  08.29: A strong bar magnet is held very close to the opening o ax6zk 1brgx 7+a80alvf a solenoid as shown in the diagram. As the magnet is moved away from the solkaba0x16a +7lvzg8 xrenoid 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 shownj (h/p;+xx-mqvxw8l d, the variable resistance in the circuit on the left is increased at a covxwhqx+ m8xl-(pj/ d; nstant 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 conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet 9hnian;qv :6mis 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 cv 6qh9nm;n i:aurrent 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 loop6od8hfly v q kp/e7i/yu:z z)2s of resistive 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.u7fz hk 6e/vlzi)d:o /yy82q p 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 thp 61 h:mzrnli87*p * lb3i xf;uk,yjwde 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 reoqf* ck2aoag bv2 (e29sistance 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, conduck bv6-o*nx (y b:z.ytuting wire loop sits 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 one of the following effects best des *6z-(.onbubyt kyx: vcribes the result of this field increase?

  16.47: Two small loops of wire are loc4 /-i5lm 9gpbizm3 y/azg n2jiated close to a wire with conventional current directed up the page. A scientist then moves the loops away from the curre /z2anzm-jgi543g 9 bypl im/int as shown. What is the orientation of the conventional current in each loop while this occurs?

  17.35: A metal bar is moving to the lefyrh 8jbl49 0glt 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 onh8ly grj9l 4b0e 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 solckn+8j /qds589 iia8bbly+0omw le66 s xnn7renoid passes through the circuit as shown. The magnetic field of the solenoid, dirmsla78i+ 6 jrdie/+kc9 ybs0bn5nwolx6 n8 8qected 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 is dh-n3f2kpx64jzxt il+ ( d 7mh1jddt;wecreasing in time. A constant emf ξ is produced for the square loopitkl;+ 6( 3 xtz 1dfnmjx4dhj2p-hw7d 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 magnitude of the voltmeter’s reading?