94.20: A magnet is dropped through a vertical copper2qs28b w; hyiz pipe slightly larger than the magnet. Re22biyhs wq8 ;zlative to the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an inducedjp;gn*86nv- i zpccz x 5pa1lc q.5fu7 current in a conductor by a magnetic field ux6.7n v-n;1 c f5p5 jqpl8c*capg zzicould be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is equivalent to z (;gr:w)bttsrf // eiwhich one of tw r/)ef btt /zr(;i:gshe following?

  04.34: A square loop is placed in a uniform mag9enin/8 (qp kxv w:e6anetic field perpendicular to the plane of the loop a(vxwe ik9p en8n6:a/q s shown. The loop is 0.5 meters on 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 into9a5kt2;iyx qe9klb/ w the page. The wire ex ;qbe ya2/l9xt5kkiw9periences an induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a vel*2mc+s i ffv5;fkhn-gocity v through a magnetic field and experiences an induced charge separat*ncmffi sk2 h+-v5f;g ion as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the0w x5yvst4n2/ bpw-uc right on two 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 ravctuwy0w 2 np4bs/5- xils?

  00.10: When a wire moving through a magnetic field has a voltage induced begv-0 a6rzou4 ctween the w 6zvo0u4ca -rgire’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 copper rod has constant velocity 0.30 m/s travk2aytx zkl6qek0- k(+eling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is 2 k zkl(-eatkkxq06 y+the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its opening is perpende p4 dhit.f4:uicular to the circuit contain.fteu4 4pid:h ing the two light bulbs as drawn in figure 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 are assumed to be clobtkln 3w)1g(b se to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galvanometer needle in bwglb1k3 )n( tthe right-hand circuit move in response to this change?

  08.29: A strong bar magnet is held very close to the ope4l34wegrd733 zq,y jxohsb3n ning of a solenoid as shown in the diagram. 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 inducedy4odxn,w3 j3 r7eb3hgq 3zs4l current?

  09.37: For the figure shown, the variable resistance in the circ0/n1j9c +tfqo5dwvh e uit 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 conventional current thro0 5j /ch wnv9q+tdoef1ugh the resistor in the right-hand circuit?

  10.39: A strong bar magnl /6 p*ck,9*i +cprzs4qgzofeet is 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 through the resistor shown is dir4*o 6cziqpfl/crps z e,+k9g *ected 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 next to xb:3o.w1 ljjht-gja,i st2k 7 each other as in the figure. The circular loop on the left is connected to a constantg h-jjjko 3.ts i7l,2bwaxt1: 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 t r pww8h)y.r1kdgu8p;he 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 3+5d z klypi361mnnydvariable 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 perpendij4w w-sh. cia,cular to a spatially uniform mag w,4-wj csi.ahnetic 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 conve7j0; jpmhmhm /7q rt)kntional curp);krhh q tj7mmmj/70rent 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 this occurs?

  17.35: A metal bar is moving to the left acr /+r shh9:stlz k-xrbpw7 7uqkz6.kw 20vhz(uoss 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 one of the following choices cl. w 9+uk0h/hx(zwpuzrq sv:tz6s7 hr27b-kkorrectly 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 solec3od.l3 :1 xx9 aymbgw6rnj c:noid passes through the circuit as shown. The magnetic field of the s69gxwdalbm 3c3o nry:1x:. jcolenoid, 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 the ps.5if q4u vmr9lane of the page is decreasing in time. A constant emf ξ is prf9q .vs4i5mu roduced 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 magnitude of the voltmeter’s reading?