94.20: A magnet is dro/ y79 6zgngvwu7b5qb qpped through a vertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magnet in the v6n7q ub7/ q9 g5zybwgpipe falls:

  01.30: Lenz's law concerning the direction of u*eq5;um lnqk. sf4)qan induced current in a conductor by a magnetic field could be a restanu*q5qe )m.lksq f4u;tement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is equivale4g6hs h-b9 x)w8p jklxnt to which o6 4 8hs)xlph-x kjwgb9ne of the following?

  04.34: A square loop is placed in a uniform magnetic field perpendbqepza83li,+ r wqr 40icular 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 8br eqr03p, lzw+aiq4 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 d/o vjsdg)n8f5x7v vpad4g(gt0h,z: y ;;yhdexperiences an induced charge separation as shown. Which way isdag;sjv;8o h)5yggxv4,(dvpt zf dd / ny7h:0 the wire moving?

  00.20: A wire moves with a velorl7:w uor:c4qp w00fse*+blq:dfehupb / /b/city v through a magnetic field and experiences an induce4:d0or0:lf/ qwe plfpcubus*qh/wb7/:br +ed charge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on ttqd qgfxj.:* ,zih9- two conducting rails. To make an induced current i in thgq9*-:fz,tdh. x qtj ie 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/2e kx+eq/tu q(2gvfm a magnetic field has a voltage induced between the 2/k2vfx/meqtug( qe+wire’s 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 has constant velocity 0.30 m/s traveling througtrbs0zn(j + n4h a uniform magnetic field of 0.060 T. Thr0(bz+ st4nj ne 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 so that its opening is perpendicul0zft9ei624d(ct h7 ilb b- ce*qe9y spar 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 y9e4*ibp0 fde9hz tctq6(- elsbi72c 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 thqvdw g5 m-2qk+: ix*sle diagram (which are assumed to be close to each other), the resistance of the left-hand circuit is slowly increased. In which directiqi2-d5km+ gwx:sl v*qon 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 o7-voe ooqm, wxsg3*8chvwl2r+dr7tg 2(df1q f a solenoid as shown in the diagram. As the magnet is moved away from *h w 81r32ovt,gsd2vq locog-+ (efrqxm77dwthe 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 circiwiyg p)ofu)zzt(9an238pq.wi. n) xuit 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 is the conventional current through the resistor in the xfowiu)(i8zpti .z g)na9.23w p) yqnright-hand circuit?

  10.39: A strong bar magnet is held very close to the opening of a solenw 5qim lc:3 /an8jpu.ooid as shown in the diagram. As the magnet is moved to th 8n.5/c jl ia:m3uowqpe 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 tur9 a/l89h uaro 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 th auh/ar9u 98rle 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 c.csohy3d,w* e 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, th f5l;l v6)q v8fvbm6tue 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 ctfg s)zk:z9pn m ,3k7wiqq:(5fgn d. loop sits in a plane perpendicular to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strength steadi nwpz5 3:mfcgs(g7,q9 kifnd )q.kt:zly increases with time. Which one of the following effects best describes the result of this field increase?

  16.47: Two small loops of wireqg t*r0ve*nnt8- ys8upekns+7 )dy 6m are located close to a wire with conventional current directed up the page. A scientist then moves the loops+mr8 kve 6-sntesgq87yy)tn0dn* u*p 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 tql0 w*dvuw(01rmlia.k w,/ athe 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 th0wtau/.(0a ,wivwl lk1rmdq * e 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 circuit as shown. The ffxun fj eq3.rpi42)-magnetic fiel)qfp3j- 4u f.xn2ie frd of 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 decreasx4jll khv29 17 lvmas7yl m1s-ing 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 vol4mm-a7711vhx l lkylssv9 j2ltmeter connected to the corners through the center of the loop. What is the magnitude of the voltmeter’s reading?