94.20: A magnet is dropped through a 9gudy3bhv (,q vertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magne d9vy(gbu,q 3ht in the pipe falls:

  01.30: Lenz's law concerning the direc:x0 *ii ;e gxhrl4:uofj7 fz;ation of an induced current in a conductor by a magnetic field could be a restatem;g: ar x4*i:il70jzxfheuof;ent of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is equival(kk+gd tfp/ s95t j0 y9stwof,ent to which one oftt+oktfj p5,9 gk(0ds 9 /wysf the following?

  04.34: A square loop is placed in a p(m+++/uimx -dbo zbh*j ug5 runiform 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 umh+d* r+ p5ij m( +ouzxbg-b/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 tft2 tj10mhb(m hrough a magnetic field directed into the page. The wire experiences an ittbmf( 2hmj01nduced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a. , c4cfqlbog4v,, jul magnetic field and experiences an induced charge separati,q,g4bc fo4j,vl. uc lon as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar 9b;y8 i*mzgbe 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 area containbzgy i; 8*m9beed within the conducting rails?

  00.10: When a wire moving through a magnetic field has a voltage induc4uksz w 6k5hl(ed between the wire’su5(6 ksl4w hzk ends, 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 hahu9,yr l w7dlav.3yj:4- vr gfs constant velocity 0.30 m/s traveling through a uniform df hy a vv.ry7-:rg9l 4lu3,wjmagnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on rso0u **(ujj qso 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 time at the same rate for each circuit. Rank the circuits fjj(* o0q* suuror the brightness of the bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (which are ascrgwrp/6-xzwx3r ivl2;4u h- tm+b:ksumed 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 right-hand cipl- i h/wx3x2+t zu-vmb4rw:rc6;grk rcuit move in response to this change?

  08.29: A strong bar magnet is held very close to l acaw.*:n+51*4x9hypzz bbo c :q iauthe opening of a solenoid as shown in the diagram. As the magnet is moved away from the h+z qy c 4c: bua*1:alnpzx*aw.5obi9solenoid 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 variable resistance in the circuit on the le+rsy l2 4.b 5kuq)ui;3k kzmruft 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 circu)l5 k4r +rzybskq.uu um3k2i ;it 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 closi/894yj se.e.sdbs 8 e0kylt he 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 ly9dsjt eess 8k./e04byi8. h “??” in the diagram represent?

  14.34: Two circular loops of resistive wire are placed ne yn2xngov;-k/ l0d-p lxt to each other as in the fig-v/pln0xd;y 2o gnk-lure. 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-hand loop (as viewed in the figure from above)?

  11.41: For the figure shown, the variable res)nvw1; qfz l7kistance 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/dm yvu cerm/uu +)e:8 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 .v k0om6-8gs a:zvjbn whm *lhw- -iy:perpendicular to a spatially uniform magnetic field pointing into the plane ofv: 6vy-iak-gzhh:jm0.lwo wn 8m-*s b 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 are located close to ae/w *epf;ix*a4mbs8jwc .io2 wire with conventional current direcs;mpw *w*2.j8 /cebefaii4x oted 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?

  17.35: A metal bar is moving to the left vq4o/ihc8( i okpgbszm// 65nu )qr)hacross 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 magni)v5o pgmu4/b) c/rqh/z(ok6n s8qiihtude of the currents through each resistor at the instant shown?

  08.50:. An infinitely long solenoid passes through o7-.;t ljsntng uiu0fpy. w0- the circuit as shown. The magnetic field of the solenoid, directed iny;- 0j. pnni olsw u-ugtt7f0.to 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 plane of the page is decreasi9n fv8g3+frzb8l8b zdppo+- jng in time. A constant emf ξ is produced for the square loop enclosing the field in the figure. The square loop has three id-8+j+vg8 ozpfdbzlf 9 pnb 3r8entical 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?