94.20: A magnet is drop2jc* 7 ylei9b61 ,vyiub/ydnm ped through a vertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the ma vbij7l,y69yibe2nu* 1/cd m ygnet in the pipe falls:

  01.30: Lenz's law concernifk+v4su20el rng the direction of an induced current in a conductor by a magnetic field cou4+klve0r usf 2ld be a restatement of

  11.25: The product (3 Teslas) × (2 dbsr );d)pr5lkp, 7lvmeters) × (4 meters/second) is equivalent to which one of the f,lvrkdbp ;plr)7ds 5)ollowing?

  04.34: A square loop is placemimu846xw3 tbb-js37qwl zh x) *5ave d in a uniform magnetic field perpendicular to the planxv 4xs3)8bz a6l 7-w btei3 qh5jmwu*me 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 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 n ehlh0ke(wr- 8w .hx2experiences an induced charge separation as shown. Which w e0 lw.h-h(ewkh2nx r8ay is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and experi)1 .sdp/bv uzys sk6.eences an induced charge separation as shown. What is the direction of the magnetic field?/.ss .)b depuksyz16v

  05.33: The figure below shows a bar mo+k;y/he/ /3 fzw wwpcuf stu,9ving to the right on two conducting rails. Top3eut/ wzcusw //fy9;wh +,fk make 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 movi)fnuhrn;d c4m4 iu3 e62 yf-wtng through a magnetic field has a voltage induced between the wire’s ends, t 2m4eurcn 4uwdi ty- )3f6nhf;hat 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 0a vi1db.ui8tn 6b 8zx9.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potential diz8 b1 i.8n9vd6xu tbiafference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its opening is perpendicularcnyyd3a 9; u3u-tenc 6 to the circuit containing the two light bulbs as drawn iy3 ycuan69;cu n-t3den 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 to be close w36-mck(bze a to each other), the resistance of the left-hmcb w( a-k6ze3and 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 solenoid amb;e6fvm ;dzcqg : (/5dvh r+bge ix/5s shown in the diagram. As the magnet is moved away from the solenoid at constant speed, what is the direction of conventional currentq 5v;db if6/m 5cg;v/(bhm +eex:dzg r 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 left lc( 5ekz 3(hg,o*u;h1p+clof/a khl v is increased at a constant rate lah vlkchohp* (lu/g1e5c k;o3 ,(f+z. 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 openi4 i5cofa u5u6wng 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 sole5fwu4o6c 5ui anoid and which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of resistive wire are placed next to eacq-l1.+a nwrgs:+fdo v b p6/boh other as in the figure. The circular loor n6:1psqgblb fov ad+.+w /-op 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 resistance of the ou .8 4 qf*qj3lhdbkiwudp3uv71ter 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 qn s unr9 q2tv,)fpat)0w ,g6oof 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 sitst1u0s.j(96jribrbn-o d xm(ag 1xr7k in a plane perpendicular to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic fiio-91x(rns.rb60 1(mtj 7 dagkuxb jreld 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 w u5ehy5as cd:++62w/4 iyd bu9ii fdbare 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 or bw:s6 iwd eudfb+/5+ac5 yiuyd42i 9hientation of the conventional current in each loop while this occurs?

  17.35: A metal bar is moving to th2e x11 zmnfm+o4:ouze e left 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 1zux1e fzmn2+e4o :omthe relation between the magnitude of the currents through each resistor at the instant shown?

  08.50:. An infinitely long solenoid passes thropip5yh4q./;y ed9zjm5 6zu a cugh the circuit as shown. The magnetic field of the so9z5m adi.y/qe phu;4p j5z6cylenoid, 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 directedd-1m1-my9d2 sb7*qfu khyzukt 6+cvo 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 figure. The square loop has three identical light bulbs of resistance R in it and an ideal voltmeter connected to the corners througdm9q*6ft ck 1zymyb+vusuh--k2o 71dh the center of the loop. What is the magnitude of the voltmeter’s reading?