94.20: A magnet is dropped through a vertical cd ) 2d,kb.h, x7f l axfb0p,/c3xllexiopper pipe slightly larger than the magnet. Relative to thfp,xi,k) e,x3fbdabxld l ./72 xlc 0he speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the9.a 0truw)m: iuny)v k direction of an induced current in a conductor by a magnetic field coul.v :)mknuaw i)rt9yu0d be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 metezfn5w t ;bcoen0s-7; j3.orptrs/second) is equivalent to whi 7ntfo3zws .;cn;-oj5 bp0tre ch one of the following?

  04.34: A square loop is placed in a uniforms3f/ - q;*hjp)tymuy r 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 yf-;yupmsq 3t h /j*)ra 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 thh.sa2,+ ss9+i qahic orough a magnetic field directed into the page. The wire experiences an induced charge separation as shown. Which way is the ws,hs a9oiish+a.c q +2ire moving?

  00.20: A wire moves with a velocity v through a magnetc1c8,,7ts -e kopcwfwxiyj ;)ic field and experiences an induced charge separation as shown. What is tyikxw 8t-;s)1c f,,jc7ecpowhe direction of the magnetic field?

  05.33: The figure below shows a bar moving to tni lf,mkly,: 3he right on two conducting rails. To make an induced current i in the direction indicated, in what direction would the magnetic field be ikf ,ynm3l ,i:ln the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field has ab0j+94dvqde n voltage induced between the wire’s end dn409+djb vqes, 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 traveling throughj; /5,htilnko8gbeo*t 9d b3j a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potential difjgb dt b5 /o9 ie*ohn3;jl,t8kference induced across the rod’s length?

  04.42: A solenoid is orie wryjzh8n9:y nqa(x-( nted 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 ney 8zh(r (a:qny wjx9n-gligible 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 bzbj qc.29ffaom8 .zzg: hj0)diagram (which are assumed to be close to each other), the resistance of the 09fa goh)z..8 cfjzzb: bj qm2left-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 soliyk ke q/t *ln0ojfgc69;o -f7enoid as shown in the diagram. As the magnet is moved away from the solenoid at constant speed, what is thegcnl0ek qk o t9ff*oj -6/yi;7 direction of conventional current through 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, kmlaf-p2o b9 n8/yhc:the variable resistance in 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 convlofc ymp/:h-kn ba892 entional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is held very close to the opening of a shtvj09j69 lbvc )p+rm olenoid 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 induced current in the solenoijlrcjb t+hp9v9)m v6 0d and which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of resis a i/0it:qwf*dtive wire are placed next to each other as in the figure. The circular loop o/iwi:0qd*f at n 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-hand loop (as viewed in the figure from above)?

  11.41: For the figure se)m32ri 1zfu srnyr;bq .i ehm8 1l,(bhown, 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 resistance of t( 1ilu6 avt5t( ppr03jrviecio 6y.c4he 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 ajhej9 evoa2fc4 (zm09 plane perpendicular to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strength steadily increaseve0jzaj 4f99ceh om(2s with time. Which one of the following effects best describes the result of this field increase?

  16.47: Two small loops of wx0fw*0a2*)ugqp:9 v bqy lfch ire are located close to a wire with conventional current directed up the page. A scientist then b qp*ch)w:* 0yf ulv 0x2g9qfamoves 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 le00kq wkz6hf/tq 2 xn72 earx5)isjcu )ft across 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 indicates the direction of the conventional current in the resistors and the relation between the magnitude of the currents through each resistor at the 0 )a5n6 seu/qx 7ktzcqhkx0i2 f2wrj )instant shown?

  08.50:. An infinitely long solenoid paunxr.0k +c3t nsses through the circuit as shown. The magnetic field of the soleurxkn.n+t c 30noid, 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 pl+1ovm; sdl0pq 0ob9wl 3s)uff ane of the page is decreasing in time. A constant emf ξ is produced for the square loop enclosing the fieq01sfp+ l)o;usv olb9f3 0w dmld 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?