94.20: A magnet is dropped through a vertical cop. ct9wa,0i )ejf2nz ncper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magnet in the pipe falln0 fnai2w,j)c . 9cztes:

  01.30: Lenz's law concerning t2hlg +fqqx :mey 02nz)he direction of an induced current in a conductor by a magnetic field could be a rxzmq 0h +y2f: )gnqel2estatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/gzvq/d h:7a 6/lp l/t rbd,yy7second) is equivalent to which one of the fogdryy/a bldl:7, q6vz t/7p/hllowing?

  04.34: A square loop is placed in a uniform magna;djz3py(snr f-ao9. etic 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 stren;ynrs9(. a-zjp o 3dafgth 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 mi(xto vv:l8; be6dm997i uqzhxkh6y ; agnetic field directed into the page. The wire experiences an induced charge separation as shown. Whi;dk6vyhv9; t7bi:iz86xxe u qh(9mo lch way is the wire moving?

  00.20: A wire moves with a velrw-a/mm*am+. g r0 wm;hmb5dqocity v through a magnetic field and experiences an induced charge separati +;m5rqwbw/.*am gmmadmr- 0hon as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar movingy+(rf xblmfcd r+/ wur(c0bit6a5l )j + 16xas 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 contained within the conducti6( xrsar(di l+ jrfab6/1lucw+y5b0+mt xc)fng rails?

  00.10: When a wire moving through a magnetic fizb; k1+w35 me utitd8teld has a voltage induced between the wire’s ends, that volttt e35dm;i+u1t8bwkz age 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 ce8m hk,pmj1 9 lqmt):lonstant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpme:t h91m)l,k8mlq pjendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its open 7a8vzhu05eu ning 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, nuh ze58u0va7shown 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 t 6 -h8dn vdac t2o0fp;+dey,zche diagram (which are assumed to be close to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the ydt;8 nd,cpvfe0a2o c +d 6-zhgalvanometer 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 solepwljm068mv mt k(-h w;noid as shown in the diagram. As tm0j(mhk tv;plw m-68whe magnet is moved 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 variable r msl eqoydc,kyl77: )6esistance 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 i ,slymqe ly) 6o:7c7dks the conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is held very close to 3 s*,k s qgfaek;hb6-nthe 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 nb ;h6sk ,*eqgkf3 sa-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 in 7d+;4 e*xt flluj kvuu lw*llli)r. 6: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 changing, what i6xrujl.u t4;d*ull)*lvwi kl7:e+ f ls 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 resistanc bnac;l 4xbj qk0j8kz,,m5 bw8e 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 the innercircuit sazoe 8 e +aj)vqih4s.e l3k(6$R_{inner}$ 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 perpe.zw(j7fk j:ksw8*w*yd h eije*pqb*(ndicular 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 describes the result ow*z7yekbsfdh (qjj*8:pwi e*k(w j*.f this field increase?

  16.47: Two small loops of wire are located close to a wire with conve bz;a; zbh8y(zb(ms-/ml8 20hxwoa rentional current directed up the page. A scientist then moves the loops away from the current as shown. What is the orientation of the conventional c2; m axzr/;oes0hb-8y l( (bzm hba8zwurrent in each loop while this occurs?

  17.35: A metal bar is moving to the left across a set of frictionless con3 l hu w lg-yo/ hdg9e-9x8h/wjzr.;lmducting rails as seen in the figure. Throughout the regumwgd/ l .8 xllh oje-;9hwhrg3-9yz /ion 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 instant shown?

  08.50:. An infinitely long solenoid passes through the circui*qu9ou gr .v8b-ke uj8t as shown. The magnetic field of the solenoid, directed into theu8-kv.*b qej r8og9uu
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 decreasing in timdi1 7b+xq 6qx0d8j bjze. 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 through the center of the loop. What is tbz+ 7 x0xd 68qibj1jdqhe magnitude of the voltmeter’s reading?