94.20: A magnet is dropped lri 9b.oj l(2,ax4wri1(pbanthrough a vertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magnet in the p( pi.na l,b(iwxb9lr 42ora1jipe falls:

  01.30: Lenz's law concerning the direction of au )gn4 i:h+f xzn34bntqp5.frn induced current in a conductor by a magnetic field could be a restatementbri4x4z.gnfqf+5u n) :hn 3pt of

  11.25: The product (3 Teslas) × (2 meters) × (4 i78zm+x wmbg 4meters/second) is equivalent to which one of the fozmi+x4 bm8g7 wllowing?

  04.34: A square loop is placed in a 5:gbg (fv0hnr uniform magnetic field perpendicular to the plane of the loop as shown. The loop is 0.5 metnrhgf0 5gv:b( ers 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 magt7kjc 9 mv0vwqt-my-8netic field directed into the page. The wire experiences an induced charge sepaq-v8wjmtc0-7yv 9m ktration as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and expef06wf 0vg9+sm:bjof sriences a mj0s f:v s0fb9wgf6o+n induced charge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar movi1 +i8c+,sh*ide 4a fte n utvves1lp8/ng to the right on two conducting rails. To make an induced current i in the direction indicated, in what direction tsie*pe 1a/s881vdt c4uvlh+n ,i+fe would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire movywojpri8 x5r.i h2ukc9ut153*.s)veuvla3 w ing through a magnetic field has a voltage induced between the wire’s ends, that voltage is *c.2artuwel.soi5 v kryui3jx 93h5 vw8)u 1 p
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 throu7 2(pusb.ucyjz, msk4gh a uniform magnetic field of 0.060 T. The rod, v cus,2 u74zms(j.pbykelocity, 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 perpendicular to thens )i ,r71tlrq2 o/nge 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 circuiq,t lsoi n7n)e1r/g2r ts for the brightness of the bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids showotj 3v kfvnt*ip2-8 f,n in the 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 galvanometer needle in the right-handin,-f vpktfto 328 vj* circuit move in response to this change?

  08.29: A strong bar magnet is held very close to the opnj.-8 xtyd6qp ening 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 8x. dpn6j ytq-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 r0;hmp g *k1j -uefkfwi :8arml:d+7acesistance 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 is the convh-1f7a;re +i mu* kpacdlwgk8fm: 0j:entional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is held vemahiag7 o; ,4jry close to the 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. Whaoi;mga7 ,jah4 t 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 otherc/ .w,6agwqq fabb97o) d7nhh 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 is67,on /bhcd.bq hg)a7 qfw9aw 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 vafkz, ) mjqyf31sh7 xc-b j*s,hriable 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 variabfl6wtm,d kz02 le 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 on,8lk) w t by m+mllebjh9 brou/21z*wr(; s7wire loop sits in a plane perpendicular to a spatially uniform magnetic field pointing into the plane of the paguj2 w9 b1ol8b/tb rwk,ozs h(y*em;)rmn+ 7ll e as shown. The magnetic field 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 are located closo6 e5r rf,dmn*hlq+b, e to a wire with conventional current directed up the page. A scientist then moves the loops away from the current as show ,d+hebf, mn5rr6ol* qn. What is the orientation of the conventional current in each loop while this occurs?

  17.35: A metal bar is moving to the left acrok/* kcd;bby8hy+1wcq ss 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 lh ;8bkckywdc/yq+*b1 abeled 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;hzk/nb pee )ef2xr+3 zo-9ik rsii7. through the circuit as shown. The magnetic field of th3)ip9iskekhie2x rb -o+; nf.7ze/zr e 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 decrs,z-z-- vscep3ie xu+ easing in time. A constant emf ξ is produced for the square loop enclosing the field in the figure. The square looz-s e- iv-peux,+3s czp 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?