94.20: A magnet is d --/dzfkfxwg. y.zp4+3hue cxropped through a vertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the mage.x+ypwu--dx/ .z 3zf g4 chkfnet in the pipe falls:

  01.30: Lenz's law concerning the direction of a2v; 5ajqr6 tzvn induced current in a conductor by a magnetic field could be a rest;v5j6v 2trqz aatement of

  11.25: The product (3 Teslas) × (2 mmd k61,(; 4kaueawpa geters) × (4 meters/second) is equivalent to whicdagw pae;ku64a,m (1k h one of the following?

  04.34: A square loop is pl74b8d8nv mbzevfz . .baced in a uniform magnetic field perpendicular to the plane of the loop as shown. The loop is 0.5 meters on a side and thz.zvm8e87bn v4b .dfbe 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 directed into the pawwja(y6dhrg w4p a6 /d3dv0 ;nxv57sot5tk3ige. The wire experiences an indudrt;iw6gd0sx3t 5a5pn k73(4vdh aw/ w6ojvyced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and experienc3+ph:rl 6). rvhptvux es an induced charge sepv r +6rtl:p)3.vhhx uparation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a ohq 1i8modm +l 7+ frkg3*4wcqbar moving to the right on two conducting rails. To make an induced current i in the direction indicated, in what direction would 487dhkgmo1q i*omcq+3lfr +w the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving+ 85ow40m u0nqqtfplk through a magnetic field has a voltage induced between the wire’s ekmt owfqp 0+q85l04nunds, 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 my e;p-ldg (/vv/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potential difference ind; v d(p/lye-gvuced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its opening is perpyqumtlic 9+01f. 67 e y8zyidlendicular to the circuit containing the two light bulbs as draw8y.dy9+y70lzmu cte1 6flq iin 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 labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (wx , vu6n ;2hgikov7e2ehich 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-hand circuit move inhvvo,egi2 u7kx6en2 ; response to this change?

  08.29: A strong bar magnet is held very close to the opening of a solenmye ,cru1 81u, tuh6rfoid 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 and what is the direction of the force on the magnet because6hreu,tcf mu,8ry 1u 1 of the induced current?

  09.37: For the figure shown, the variable resisf5(x 4b+qi5dwsw9l jftance in the circuit on the left is increased at a constant rate. Whatfb9 4 qsi 55f(xw+jldw 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 right-hand circuit?

  10.39: A strong bar magnet is held very close to thec4qwouu:2+y0 cib uu) opening of a solenoid as shown in the diagram. As the magnet is moved to the left towau oc0:+yqc4ui2 b uu)wrd 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 rb.f-cow0 7x yfh f; dr)/.tcdvesistive 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 linewc; )d7ry .vf.d/cfhfto-0 bxarly 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 the right-hand loop (as viewed in the figure from above)?

  11.41: For the figure shown, the vart 4wk,n c*nroo x.a26xiable 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, ty.a 6)d ffdyo9ozl+g4he 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 wird +(bhc+t i)rre 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)irrd+ b+ t(chly 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 close to a wire with conventional,e3rgb7 8iekk current directed up the page. A scientist then moves the loops away from the current as sg 8,73ei kkrebhown. What is the orientation of the conventional current in each loop while this occurs?

  17.35: A metal bar is movin dv z:4 oxjam bag-/1pc).b/bmg to the left across a set of frictionless conducting railmxp:1agacbomd 4b- v.b )/ /jzs 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 shown?

  08.50:. An infinitely long solenoidsf5u*e 8wyuay //6we y passes through the circuit as shown. The mage/e *s5wf yu6uy 8ayw/netic field 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 pagc67aiwpkt,*er0.y 5 hv57wksjkyd r/ e is decreasing 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 w*hrj0k d5a vwetk yy s6cp/r. 775i,kin it and an ideal voltmeter connected to the corners through the center of the loop. What is the magnitude of the voltmeter’s reading?