94.20: A magnet is dropped through a vertical copper pipe sligha duta -6.. aox-spmu 0ek;0vutly larger than the magnet. Relative to the speed it would fall in air, the magnetemt u-u-0.pd6u0.axasva k;o in the pipe falls:

  01.30: Lenz's law concef1 hnter8.zlsy,oy(*ipdx547k mn ( erning the direction of an induced current in a conductor by a magnetic field could be a 71 *p ie,nye8 l(m4thdsx nr5o.yfk z(restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is equivalent+ 7oyh;jaksv)0u gz8b to which one of th8+oub h )ag07s zjv;yke following?

  04.34: A square loop is placed in a uniform magnetic field perpendicular totx0*hl sm 1t a,u3bs/j the plane of the loop as shown. The loop is 0.5 meters on a side and the mbjxsm1* 0ul ,at/hst3 agnetic 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 directdu:lfd 3mty( 0l;:og7r3rvteed into the page. The wire experiences an induced charge lr:3ug 0r:fttv7med3oy ld; (separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v throun; vj q 6s9o7:qi,vyoggh a magnetic field and experiences an induced charge separation a6y9;oq:nvs 7qg v ij,os shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving tr )1 gr-bgu7kmxmva;0o the right on two conducting rails. To m7rgv);xu 1mr0gb -a mkake an induced current i in the direction indicated, in what direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving througtf6 8d*e fob;:m wdf.-3w(suw0 p qfcuh a magnetic field has a voltage induced between the wire’s ends, that voltage is q*pd6dftcuwwfow mf0-u.fb8( se; 3:
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 constant6sfffgc:* (n ,y62mqhg ;sv4j 7pxclc 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. pff62y ccns jsvh:;*76m,(fcl qxg 4g What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its opening is perpendiculax.,p jk3,u cuhr 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 time at the same rate for each circuit. Rank the circuits fo, c.j,x kuuph3r the brightness of the bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram r6 gc42fo1p el(which are assumed to be close to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galvanometer needle in the fpreo 62glc1 4right-hand circuit move in response to this change?

  08.29: A strong bar magnet is held 8 -f:uh unnz/jvery close 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 uhz8-ujf :/nnthrough the resistor shown and what is the direction of the force on the magnet because of the induced current?

  09.37: For the figure shown, the varmlpks+h1 j,sf 0j,a+s iable resistance in the circuit on the left is increased at a constant rate.lsjjmf +1ss ,hka 0+p, 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 is held very close to the opening of a sees-8 /5bgboua y.c6 yolenoid as shown in 8yuo ybe6 .a/gbse-5cthe 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 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 each other as i kf 3e:4 ih.(nnes8xbin 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 chai i kb 4n:.e(nhfsex38nging, 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 oo dlue2g) 0nq)0(/ /psoev+fqh/bjg cf 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 figur; 59kldk5dh 0k jqwjf9e shown, the variable 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 perpendc3e00 ojre.g06ggxl ( q xve,picular to a spatially uniform magnetic fieldol0gj q vp(ge e,rcexg0x30 .6 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 b7 xr9hsb-3 ;:e q:ci+mhvwmi are located close to a wire with conventional current directed up the page. A scientist then moves the loops away from the current as shown. What is the ori; i9m73sh:ic +evm bw:brqh-xentation of the conventional current in each loop while this occurs?

  17.35: A metal bar is movvh:6u40t3p m/pwu ysg ing to the left across a set of frictionless conducting rails as seen in the figure. Throughout the region between the rails, there is a uniform magnetic msh/6u gwu: yt04vp3pfield 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 long solenoid passes through the circuit as showneicca5 fvgc +v6mio dyl359 2rp74:c o. The magnetic field of the solenoid, direpo:gm3459y +ci76verf 5doac cv ic2l cted 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 plann47rx j.hbija a bl9vp n4q79/e of the page is decreasing in time. A constant emf ξ is produced for the square loop enclosing the field 4pbrl/.4an7xjvj9 na qib9 h7in 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?