94.20: A magnet is dropped through a vertical copper pipe slnitm5gi 5pm;*gc,qxu8l)o:f ightly larger than the magnet. Relative to the speed it would fall in air, the magnet in the pipe fa5*igixlpc;,g q5 f:8tm) nm oulls:

  01.30: Lenz's law concerning the directiokl6,yfrs v9 y5n of an induced current in a conductor by a magnetic field could be a restatemelyk,9 v6 5rfsynt of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is equivalent0-j:wtdaq gd7 to which one of the followingdd0tqg-jaw7: ?

  04.34: A square loop is placed ;3pezy d;dpf w ne3o+5in 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 field B has a strength of 2 T. If the loop is r n;ppzd;ey3ed +ow53f otated 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 throuaotowqs.0 sfq dewx- rtu 1,1k83:- gzgh a magnetic field directed into the page. The wire experie 0gt 1kaszw-8eood f.1q,:rxtus wq-3nces an induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and exp0n.tz2j46dep.jn 8cbya9 ( rx1xuto reriences an induced charge separation as shown. What is the direction ofezxo(. 9y t1cnru8 pdj2 jrt .anx6b40 the magnetic field?

  05.33: The figure below showsu4xbnyjiivb b327za .++qe9r,x2sw n a bar moving to the 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 ar7ia z+4.ebbyb,xiqsjnu +32vxn 92wrea contained within the conducting rails?

  00.10: When a wire moving through a magneth92fa3n7(bun6qndo k ic field has a voltage induced between the wire’s ends, d2a k6bn(no 3 f9qun7hthat 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 velociiaw2- d2ek+c;d/it gkty 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 is the potential difference induced across the rod-2aid wt k2/+igedck;’s length?

  04.42: A solenoid is orientemn p7kvmg q2-zsq,01w9 gmzs+d end-on so that its opening is 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, decreases uniformly in timem0sgpzm qn 7 2vzq+gk,ms1w9- 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 be3gm h(0ox k1iio4:eil close to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the4l3: o(k hgiimx0oi1e 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 a j p4vv80vy0zof 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 dire8z0py v avj40vction of the force on the magnet because of the induced current?

  09.37: For the figure shown, the variablerh2ae+0 pbs t. resistance in the circuit on the left is increased at a constant rate. Wha apr.st2b+h0 et 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 is held verygw66tv6m0u69 sfr n3)fmegbt 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 directed from A to B. What is the direction of the force on the bar magnet because of the umn0msb3g6tfw eftr 6v)6 g 96induced 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 each *dsq ;n *ph7ltother as in the figure. The circular loop 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 (thn*ht;p ld* 7sqe 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 showiyqyj// rm a4 9+pcgi:n, the variable resistance 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 variable reh-/dd g956fjlifq-k q sistance 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 planev g0+ isd(,)zoglkx+l 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 dlv,gxli+)(kz+ 0g o sdescribes the result of this field increase?

  16.47: Two small loops of wire are located close tocnfz,c9mj88m a wire 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 this occurs? 8znc,cf89 mmj

  17.35: A metal bar is moving to the left across3thah(- a vcy0 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 indih-c0hv ata3y( cates 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 passo 9u ils7n7s)jes through the circuit as shown. The magneti sj7i 7n)lsou9c 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 field directed ibjd p *k(4lim( 8qlv7jnto 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 cm j lib((lpvd* qk7j84enter of the loop. What is the magnitude of the voltmeter’s reading?