94.20: A magnet is dropped throufm qj1k)p.z.n:j fsw)gh a vertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magnet in the pipe 1) m) qf.z:j.sw jpfknfalls:

  01.30: Lenz's law concerning the di8j.kb oq:fc ,nrection of an induced current in a conductor by a cq,: jkf8nbo.magnetic field could be a restatement of

  11.25: The product (3 Teslas) ×y4/x7 sr2mdkf (2 meters) × (4 meters/second) is equivalent to wh/ymr 2dx7skf4ich one of the following?

  04.34: A square loop is placed in a uniform magnetic field perpendicular to th,mytp5o.3ef;mdi-yi5qg ja 1e plane of the loop as shown. The loop is 0.5 meters on a side and the magnetic fii-a5t 5d ofmmigy3,.yjpe1; q eld 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 the page. The wire ag1vp20sq. s c experiences an induced chap 2c aqg0ssv1.rge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a veloe7t .v ;tmjx2lb u tysi97;s0o0 yr)aycity v through a magnetic field and experiences an induced charge separation as shown. What is the directiovjiu 7.0y;rmy2esxs70t 9at)l yotb;n of the magnetic field?

  05.33: The figure below shows a bar moving to the right on two condk 5hh,*,z ux +ebf3yxz2 fk:xjucting rails. To make an induced current i in the direction indicfh,b, y3x ejhx+kf5u z:2kz x*ated, in what direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magneticv6;f(,toegif6x .auye f d4q6 field has a voltage induced between thae f; 6fe,ugfq6 x.ivto(y d46e 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 copper rod has +dux4ee a(g4iq6 ;xbe8unq /hconstant velocity 0.30 m/s traveling through a uniform magnetic field of uaxbd e4qn/8exg4 q+;u (eih6 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 3zt2x)z3l at)ugvvz 8is perpendicular 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. Assume that the magnetic field from the solenoid, shown coming out of the plane of the page, decre3a gu82ttv3z xzv lz))ases 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 pbni 56 nhs77y(which are assumed to be close to each other), thenh7yi p 567snb 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 of a solenoid as sh jpl:g*j. pye,own 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 ,gp:ylj .* pjeof the force on the magnet because of the induced current?

  09.37: For the figure shown, the variable resistance ind9d+ynu:v y95o : xaxf 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 circuit and in what direction is the conventional current thro:vy9yda:x+ 5o9ud fxnugh the resistor in the right-hand circuit?

  10.39: A strong bar magnet is held very close to the openml4y-x bdnw9a(mlq8) ing 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 directed from A to B. What is the directim-m8 (bly9x dw qnl)4aon 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 pp9ck8m, cd; gcy/l h-ulaced next to each other as in the figure. The circular loop on the left is connected to a c;kc8yl p9d c/hg,um-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 resista6 xnp oqjc7w.*nce 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 va .8/4zc4s ggv9 (j cavv5mnk3kvkr p+driable 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 wil wj 9x2a/ -j:fs8k xptc;ieo6re 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 besti ta;j6p kl9cs2 x-w8oexfj /: describes the result of this field increase?

  16.47: Two small loops of wire are located close to a wireanzzgz (r lc;;b0t-7e with conventional current directed u7;z(0t ;el-ac brzgznp 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 cm6.0h7zu6d7 wtgh yuacross 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 correctly in66zu wt.7um0 hgy hdc7dicates 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 r0hpc ixc-+t ozip6 9/through the circuit as shown. The magnetic field of the solenoid, directedc+ 9/i6-z hxproic0pt 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 u cs m6co*p5ly 2 tx.flj*d.y/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 voltmetlms .uy5c.ct *2dp*yl f6/xojer connected to the corners through the center of the loop. What is the magnitude of the voltmeter’s reading?