94.20: A magnet is dropped through a verti4c gn,3fyowo6 cal copper pipe slightly larger than the gf3n,cyo wo 46magnet. Relative to the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law cons 0kg,7d.q)yn jw*q)h admh d6cerning the direction of an induced current in a conductor by a magnetic field could be a restatement of*d .hd7ja)khd6wny,qm0 s q)g

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/)z+i/m5 zz eqcsecond) is equivalent to which one o) ieq zc5+z/mzf the following?

  04.34: A square loop is placed in a uniform magnetic field pe b,ru 27 u)tph6qeot6srpendicular to the plane of the loop as shown. The loop is 0.5 meters on a side and h2 o,6b7tte) upq6urs 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 doq1 b4ge+y 3agirected into the page. The wire experiences an induced charge sepabo 3+eg1agq 4yration as shown. Which way is the wire moving?

  00.20: A wire moves with a velocitv h)1 5yp fsu3s5tvzzmu/y*g +y v through a magnetic field and experiences an induced s+3z1vyh*mt /)55fpv uy gsz ucharge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right ona+0fwj/ vo(xe two conducting rails. To make anj(ef/0x+av wo 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 moving through a mh3k4h qc/m f2hvi2s) zagnetic field has a voltage induced between the wire’s ends, that voltage imshkif4zc/ q32)vh 2 hs
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 0.30 m/s travy +jycf--l i/oeling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic f-/lyfy+ o cji-ield are all 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 is o:ki*-cz npvba4m519y7h yzr 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 label*cak z1royzb5 vhp4im7y: 9- ned R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (which are assumey uog bx,kl8 2ja)b,)+vu:sibd to be close to each other), the resistance of the lefb y vsu8)abkg,i,lj x:o)ub+2 t-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 closexyt3bo;s: -i m to the opening of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid at constant speed, what is the direction of conventional current through the resistor shown t-3o xys;:miband 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 l*kvfm7 *0e 91cglijgthe 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 is the conventional current through the fvg*cgml0*79e 1 ki jlresistor in the right-hand circuit?

  10.39: A strong bar magnet is held very close to th3te 3a/meli4+.wh sm de 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 w+/d 3 asem3.mhl4itefrom 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 ovl lfj jzni);bt 40-7+:kxfz he9 vxa.f resistive wire are placed next to each other as in 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 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 th;z)-aff+ljlx7bvkj 94v .i nh0t:xzee right-hand loop (as viewed in the figure from above)?

  11.41: For the figure shown, th*:q 4y (zvkjhh5oz, pae 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, tfl-m)f s*7 dgma,r + 78dvpvtc (eva;ok6v eh)he variable resistance 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 perpendicular to 61g c2 tip4mvsyefrxx83 ag/) a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strength steadily increases with time. Which o g14gyap 3isrt2 8mvfe/6c)xxne of the following effects best describes the result of this field increase?

  16.47: Two small loops of wire are located close to a w.krre1t8px2jv3n qc sm5: hq*ire with conventional current directed up the page. A scientist then moves the loops away from the current as shown. What i5h3:.tnkeqc 8p1 q m*vj2xrr ss the orientation of the conventional current in each loop while this occurs?

  17.35: A metal bar is moving to the left across a v 6j/uu3yv 8c*bd .vxyset 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 magnitude of the currents through each resistor at the instant.*yu c bvd3xj6vu y/8v shown?

  08.50:. An infinitely long solenoid passes t * s0 dnvb*yjq,p4i0zv,i,dd shrough the circuit as shown. The magnetic field of the solenoid, directed isjn0i, *0i,,qybdvpsddv *z4 nto 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 decreasis oaf33yj 3)su xg7e8ang in time. A constant emf ξ is produced for the square loop enclosing the field in the figure. The square ofxsaa3yg8j3us7) 3e 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 the magnitude of the voltmeter’s reading?