94.20: A magnet is dropped throu 6h4;knrt9 aeggh a vertical copper pipe slightly larger than the magnet. Relative to thk49gha;er t6n e speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning tyqie8sq ,dal8 qx,203ty0gkx he direction of an induced current in a conductor by a magnetic field could be a restatemg82l q ye8adkx,q,0q txs0y 3ient of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second7 )w6q qlky6jn9bhwvvi 6aa)m otx /*7) is equivalent to which one of thv6 naw)bv7xhqy/6to)6k ai9q7jw l*me following?

  04.34: A square loop isop96gw( v: z4jrdp9vl placed in a uniform magnetic field perpendicular to the plane of the loop as shown. The loop is 0.5 meters on a side and the m6g ( 9v94rzdlwpj: opvagnetic 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 the page. The wire ezyp:/y9jk . ot kvid11 d;,dyjxperiences an induced chaod.pdzt9y 1/yiv y 1k;d,jjk:rge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity (a3m) 5zrbsu 0e psv,fv through a magnetic field and experiences an induced charge separation as shown. What is the direction),uz5 0fp(aeb3mvssr of the magnetic field?

  05.33: The figure below shows a bar moving to the /sei2k ymd)b.yqx* +d right on two conducting rails. To make an induced current i in thk./xy*ye i)sm+2dqd be direction indicated, in what direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic 2k d1wp6 lojo)vub 4j9unx0p1 field has a voltage induced between the wire’s ends, thko4x 6)uj1 9nbp dv2wlj01pouat 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 .z/k tj(udd6s+ r /nnzconstant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocitzd(du nj6/r s+ /.tznky, and magnetic field are all mutually perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is orien( oiobleq02pzhx6j. 3ted end-on so that its opening is perpendicular to the circuit containing the two light bulbs as drxh3z. (j o6oi 2peq0lbawn 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 tor rxxb8t.w k:: be close to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galvanometer needx8k:b :.rwrt xle in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet is held very cl upzq* .ti7om-j n0so-ose to the opening 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 resistzo ijqpu 70o*t-n-.smor 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 resistance in the circui:jruhj 5(dut .t 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 through the resistor dhu j.jru (5:tin the right-hand circuit?

  10.39: A strong bar magnet *tsu w.dn.j)0oy vd 1tis 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 directed from A to B. Who*.dvd uts0 y1n wj).tat 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 arew r0v-9 jhm5-cbeg);5pj molq placed next to each other 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 (the center of the left-hand loop) and what is the orientation of the conventional current in the right-hag bjo05c) wrjem 9mq;p5-h-vlnd loop (as viewed in the figure from above)?

  11.41: For the figure shown, the va.o*wadmv em,/ qgt 50oriable 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 resistance of the innercircuit na7a ;vksvs* :$R_{inner}$ 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 lou,/ q3 7wumbf;zyro w*op 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 describes the result of m ,zbrf7u*;/uwwy qo3this field increase?

  16.47: Two small loops of wire are located close to a witi :eq,wo+( iid8tcgl5yd , f4re with conventional current directed up the page. A scientist then moves the loops away from the current as shown. Whaq cw l8,i t+:( og5yiefit4,ddt is the orientation of the conventional current in each loop while this occurs?

  17.35: A metal bar is 9vp*jnk5ir ab ox3m23 moving to the left across a set of frictionless conducting rails as seen in the figure. Throughk3p5 ab vnij9o3xr *2mout 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 loe ,bu,4xkx9zkng solenoid passes through the circuit as shown. The magnetic field of the solenoid, directed into the9 b,zkkxx eu,4
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 directetv6acf 4-: li0 loo0ltd 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 figuret0 -l0l4ct6i : ofvoal. 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?