94.20: A magnet is dropped through a vertical copper pipe slightly lvwvs );0 5kaglarger than the magnet. Relative to the speed it would fall in air, the magnet in the pk05 wvas) ;glvipe falls:

  01.30: Lenz's law concerningwoe /2q 7uxj(q the direction of an induced current in a conductor by a magnetic field could be a restatement ofqxw7o/ 2u( jeq

  11.25: The product (3(mb u(ci7i:yo Teslas) × (2 meters) × (4 meters/second) is equivalent to which one of the: obycim7( iu( following?

  04.34: A square loop is placed in a uniform magnetic field perpendicular to the ii1s/ ge;5pt4 k nd5uttus2 et8/.00daw mwfy plane of the loop as shown. The loop is 0.5 meters on a side and the magnet8y4 wnke.i ;0dsgu2t0 i5e dtaf 5u/ptw1/stmic 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 pa d tg. -rmh(gx6(cian;ge. The wire experiences an induced charge sepad;.-r ggh m6(itca( nxration as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v thli;l x 1z(*jqfrough a magnetic field and experiences an induced charge separatio* flz(xjli1;q n as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on tj98pyvq*zy 4 uj qz)q;wo conducting rails. To make an induced current i in the direction indicated, in what yz;j uqzv8 p9q4)*qyj direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving throug66i/r/tfy kr/ar;wwgfl5f c.h a magnetic field has a voltage induced between the w5kw.gca6w ;f6 f/flrrir// ytire’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 qx r17;t:3o/w0c xrzfecx(mq zh2 :+ dssgr:h velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 x:st /ox d3r:g;c2hrs0r f(: mq 1c7e z+xhzqwT. The 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 -gz8n-l/drw1 *osbbd9. bcxz end-on so that its opening is 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 paz1r -dn8b bgcos9lb-x.*d w/zge, 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 to be close wo1os bmk4b* *ijcj* uh7*ra ,to em ok w o*i ,hr4bb*ca*jsj7*u1ach other), the resistance of the left-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 close to the openk-m1xz8hibfo 1imb61u:+l j ee z)cb) ing of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid at constant speed, what is the direction1ez ibje86- m1+cfbl:i) )hxm1k bouz 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 l *0/yij0 yjmfresistance 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 circuijjf/00ly im*yt 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 the opening of :zh:af*fyf28y-q ooh 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. What is the direction of the force on the bar magnet because of the induced current in oyfyohah2*ff:q- z 8: the solenoid and which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of resistive wire are pl2u.e l: 2 f6-rcpvlyssaced 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 thepy2.ls lu2vc 6:-fre s 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 res tp8iilmp.e,bt+z+ ;eistance 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 innercircuit (z 3 8m3pgmd/pvpz5ch$R_{inner}$ 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 l pcf6nm c7yb+8oop sits in a plane perpendicular to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic y+ fn cmb78p6cfield strength steadily increases with time. Which one of the following effects best describes the result of this field increase?

  16.47: Two small loo6+.lq 4srvkrhmxe ; /)vrq8tgps of wire are located close to a wire with conventional current directed up the page. A scientist then moves tl+;r hqvmtgkvrs8 rx/e6 )4q .he loops 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 movm3nv x.cf4 :qzing to the 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 zxv4nfq: 3 .cmY 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 through the circuit r )el6l 6 uek/)ahq)pl as shown. The magnetic field)ale)qle/ ru6l)6kph 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 p rkesa1m-m ..3zbxa ;lage is decreasing in time. A constant emf ξ is producezxrkm.s.1 a mel;3a- bd 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 the corners through the center of the loop. What is the magnitude of the voltmeter’s reading?