94.20: A magnet is dropped through a vertical c0qenhp+*vtck6o0 ob7 opper pipe slightly larger than the magnet. e+ nhto 0kvo*qp06c7bRelative to the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced current in a conducto6e5la;h5: hnoe dio7fr by a magnetic field could be a restateil6hnoo d5a 5h f;7e:ement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is equil97l dvec6/7.xh 9 suc;qd rbbvalent to 9 d c7dc;q6.b lb7v 9xeslr/huwhich one of the following?

  04.34: A square loop is placed in a uniform magn:8wy xa:n 4 qzx7i6qjbj,ik:p48cr wtetic field perpendicular to the plane of the loop as shown. The loop is 0.5 meters on a side and the magnetic field B h t 8j w7rj4wxi: icq8b xn4:kz,:apq6yas 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 intxfs j/,c2q;ld( j4)uh6lmg ay o the page. The wire experiences an induced charge separation as mlqy(6c;ldhu /j) xsjg 4 ,2fashown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a m; zj eheiulhxjp9 4)49agnetic field and experiences an induced e4uj94x9)hl i ep;hzjcharge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right otu3+ s/1 fw-ji;bbicurl6,u on two conducting rails. To make an induced current i in the direction indicated, in what direction would the magnetic field be in the area i1-l,b i;uuu/ ct6wbj3s of+ rcontained within the conducting rails?

  00.10: When a wire moving through a ma/u581ub5k ocs jlx3 jggnetic field has a voltage induced between cks8135xjljog /u5 b uthe 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 4,h6um 8 ylth)y.q fouvelocity 0.30 m/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 induced across the rod’s l)ohq64 m.uy,8fhtyu length?

  04.42: A solenoid is oriented end-m ho4le-05d l u8dvi(xon 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 page, decreases uniformly in time at the same rate for each circuit. Rank the circuits for the brightness of the bulb labeled R1 fromvhxd u8iod (ml-540le brightest to dimmest.

  07.34 For the solenoids shown in the ic0pin- q1lj (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 galvanomejiic1p0( l qn-ter needle in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet isuvno: r/+pih0 ht63sp,uu6zcr 2h )a t held very close 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 tho6/tvrr3hc ntph +:uiuu zh)2,6sap 0rough 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 cirbz6u j:fir6f zaz:d zm-m)0 r) ,)lzktcuit on the left is increased at a constant rate. What is the direction of the magnetic field at the point P at the centezrmku)zz:a )6dmjz f ribf-)0 t z,l:6r 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 vcgox/42ult 3bamzg (du4*vi 7ery close to the opening of a solenoid as shown in the diagram. As the magnet is moved to the left3 *zbv 7guti/ 2(4d4gcmou lax 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 tz l(yoq4ex.n :o 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 tyze (4o. :qxlnhe 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 variab8v w qgf0u4i+rj+d rc3le 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 variable resistywe4c 0q o -mxffsv+77ance 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 yo va45g ej(-jt.3 c qhnka1o;a plane perpendicular to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strength steadily increases with time. Which one of the following effects best describes the result of this field increask3jc- y ahtjo.e4aogn5 (1v ;qe?

  16.47: Two small loops of wire are located close to a wire a o9ta )2btlho1(d5enwith conventional current directed etal(bd)nh2519 o otaup the page. A scientist then moves the 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 moving to the left across a s-)wnquh ud r/mddxsu/.-7m)p et of frictionless conducting rails as seen in the figure. Throughout the region between xdn-uhds)r7muwd p /-m/u)q .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 pdephf,0) w *cpcft67 solenoid passes through the circuit as shown. The magnec d 70p 6f,)pfepwc*thtic 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 page is decreasing in t dmxows*3iy5x *+:hcypjg. p,ime. A constant emf ξ is produced for the square loop enclosing the field in the figur p mg5.io*jwydsy+xx3pc h* :,e. 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?