94.20: A magnet is dropped through a wh-vyz7m /b8gipc ajr4 -t 61ivertical copper pipe slightly larger than the magnet. Relative to pytv4hm/j ac wr71--g6izi8b the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced current in a conduct l h j)mdthd:r-v q)8lf9u,9tuor h:9l)qvddt h8mtul, j)u -r9fby a magnetic field could be a restatement of

  11.25: The product (3 Teslas) × (2 met9hf 2hkk e-ff+ers) × (4 meters/second) is equivalent to which one of the follo+ fe9k f-fhhk2wing?

  04.34: A square loop is placed in a uniform ma- mtz9 bq fo40ek:c-fxgnetic 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 strezfxk q0o49- -bet c:fmngth 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 wb at8k.9+3yi z+ ega4fkq2gg fire experi24gagq k+b i9+fat zge.y8kf3ences an induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and experify d2;xnz7a1l ences an induced chardz ax17ly2 ;fnge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the righhip n7m ;i8o +nccv0k+t on two conducting rails. To make an induced current i in the direction indicated, in whic;7 n+hop0+8cmn iv kat direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a mags7ee2mosf +aj2.s(x 5bou hb) netic field has a voltage induced between the wire’s ends, that va s.h+jme b(u2so57o)sefx2b oltage 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 const*f72 8. qixz p0k/qeu.wtmp yfant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mut.0 pqtf8.zyp q/xfu2e 7ki* wmually perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so ;1awv *eck:ceks-*e ythat its opening is perpendicular to the circuit containing the two light bulbs as drawn in figure C1. For figures C2 and C3, a shv- s*ayk*k: wec;c 1eeorting 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 tocj a:1j g*t3m if0,nlct/+u ku be close to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galvanometeguin1km/ a l,:c3 f+j0 t*ujctr needle in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet ispox z*iv/mo-gasv: p/ v*lv*; held very close to the opening of a solenoid as shown in the diagram. As the magn/*:az vg pm ;vopl*ivvx-/*o set 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 resistance in the circuit obo7nml4 n91juig+ kw/n the left is increased at a constant rate. What is the direction of the magnetic field atn+ wo4ijmlkn9/gu1 b7 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 heldfh i:mdx:-o86kg n q,zlop:esn*.tm * very close to the opening of a solenoid as shown in the diao8in-dmz :q6 tp kesn*:gmlx:h,of .*gram. 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 represent?

  14.34: Two circular loops of resistive wire are placed next to each other as inspfo 7)9deh ugzz04wg+r *rr- 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 is the directord 7gz4es)f9wz- 0gr+ *uhpr ion 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 figur8.afnmwf 6 *xmhx *6pbe 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 resistance of the innerc+ nb)hlw58h0u qo:knwep *)lf4 zja3yircuit $R_{inner}$ 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 ac1svmy/ q tz)a9ik6.plane perpendicular to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strength steadily insk1 i)ym.9/ av taqcz6creases 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 t/pgtv :md+lk;o 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 conventional currevd:tgm pk+/;lnt in each loop while this occurs?

  17.35: A metal bar is moving to the left across a set of frictionless conduc r*t ab.qb-6cnxy c8rkzs6o37 ting 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 36ynrsbro. c8x k76qz*bc-tathe resistors and the relation between the magnitude of the currents through each resistor at the instant shown?

  08.50:. An infinitely long sr;ta(i5v1 :tox o)fy lolenoid passes through the circuit as shown. The magnetic field of)t:iot ryaov;lf15( x the solenoid, 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 plane of the page is d6b4o 0k tn77+i ys* ttsffkp5hecreasing 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 k4hs7* 6ok7i ytttbns5+pf0 fthe corners through the center of the loop. What is the magnitude of the voltmeter’s reading?