94.20: A magnet is dropped through a vertical copper pipe slightly larger tho1-l aug(q6t zan the magnet. Relative to the speed it would fa ga 1z6t(lq-uoll in air, the magnet in the pipe falls:

  01.30: Lenz's law conce,o4afk 6g3x+ kd6yvro rning the direction of an induced current in a conductor by a magnetic field could be a 4fgd y6o,o3akv rk +x6restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is equivalenouw :v8gxmsjx 86(k3i t to which one of tm:3vxxuo8sj 6i(g k 8whe following?

  04.34: A square loop is placed in a uniform magnetic fiel gdipd. hv x4lyd24k;2d perpendicular to the plane of the loop as shown. The loop is 0.5 meters on a side an2hgi. d;2x dpyl44vkdd the magnetic 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 tawc(;ui 2:bxjhrough a magnetic field directed into the page. The wire experiences an induced charge separation as shown. Which way is t b ac;2xj:uwi(he wire moving?

  00.20: A wire moves with a velocity v through a ni :m;yt -0rjug;t9r e2qtyfsd/ (+g umagnetic field and experiences an indud2;ey;/+qiuy9 ugsttnr:gj 0(trf- mced charge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on two conducswgocu 2): )nsf0 x/qzting rails. To make an induced current i in the direction f/s g) n2oczx:qu0ws) indicated, in what direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving ,m:rb .bmopskdp 8:+ othrough a magnetic field has a voltage induced between the wire’s endoppmsm 8rb: :+., obdks, 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 c+ yj c)6 eb3nld: .0yjjmaoz-uopper rod has constant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are jjj)z ya3 -blyo +0.6 n:uedcmall 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 o:lz zkx.,;wz 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 time at the same rate for each circuit. Rank the circuits for the brightness of the bulb labeled R1 frwz.;zlo, :z kxom brightest to dimmest.

  07.34 For the solenoids s qyv19 b6u/z+qwvxxpp: 6tsv44cvi k )hown in the diagram (which are assumed to be close to each other),k6c t wx/ 9pyx4+uqszivv:bp)6v 4 1vq the 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 mtg8 .a(t ;s,ynr5hkr close to the opening of a solenoid as shown in the diagram. As the magnet is morm8;.t,n(s5k r h taygved away from the solenoid at constant speed, what is the 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, the variab,:9f se7ax8ooqtrdv* gh z2i: le resistance in the circuit on the left is 9g*q iea,r7z osd2xo8fh:t: v 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 in the right-hand circuit?

  10.39: A strong bar magne gjlo:3q xi l*2.togh+0vvc0;b(qmott is 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. 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 repr( 032qtl+ql *voogig:;j v 0xh mcbo.tesent?

  14.34: Two circular loops oyw*ns2 h ((catfs+e0qf resistive wire are placed next to each other as in the figure. The circular loop on the q+tyw0s*c s2(hn a(e fleft 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*u ztcmc;;.(,p bl)vic i7(u pdatv*s shown, 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 resistanz7 7pke0xaalme38/ dzkw(( szce 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 w.ky (1wzx )pzqg9y j.ka7ed,xire 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 best desc yk7,zzedpxka yw9.g 1 ).(xjqribes the result of this field increase?

  16.47: Two small loops of wire are lovm*7( rx5j;mmfa,tcl cated 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 orientation of the conven;cmlmr*x tfav(,57 mj tional current in each loop while this occurs?

  17.35: A metal bar is moving to the left across a set of frictionlg ,thmc,iy2vse9q/3 ness 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 i gqs,vn3ey t/9c2hm, through each resistor at the instant shown?

  08.50:. An infinitely long solenoid passes through the c:.r(in487p3e:x.elpl bvr iuvo mpk4 ircuit as shown. The magnetic field of the solenoid, dn:lvouep x7 r :4vi b43pr8epi.m.k(lirected 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 thf8 cv7yw+z 90 s;(f sxtzr0ktae 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 identicaf 0avk szytw0;s8x 7f tcz9r(+l 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?