94.20: A magnet is dropped through av*q(2g7m:gw cu ns5si5 aygv2,lk7 ea vertical copper pipe slightly larger than tcgu: vawvy5es2k52 (s 7agm7i*,nlgq he magnet. Relative to the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerninglq1e9t(8o qhq the direction of an induced current in a conductor by a magnetic field could be a restatement of e91qoh(tqql8

  11.25: The product (3 Teslas) × (2 methmmy:yh0 lqtkj )6:4mers) × (4 meters/second) is equivalent to which one of the following6hl4:qjy ):m khmym t0?

  04.34: A square loop is placed in e.-n:g8hb d j1c 2gazwa uniform magnetic field perpendicular to the plane of the loop as shown. The loop is 0.5 megahje1dg2cn .bw 8:-zters 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 magnetic field directed into the page. Tzq1e 8yyl 8oxsr2 yq04u;+ -rut 7uyvthe wire experiences an induced charge separation as uoruy1yq278s 0t lt ;-r4ey+ uq8zxvy shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v throughsv.)i )rw 6ot,,eazoi a magnetic field and experiences an induced at, ,iw)v z6.orieso)charge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right *;s bt l(nexk)on two conducting rails. To make an induced current i in th* knbl(est;x)e direction indicated, in what direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving throug)hvek 1q4nh-pyi:h e+h a magnetic field has a voltage induced between the wpe+) - hhq1:knhviy e4ire’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/ssq :7e+p)ochh traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What ho7) :+cesqh pis the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its openig4mka:i5ro jf g /+ (i vt7z9*dt;uaanng 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+49kiv u:gagir (nmjzftoa/a7*d5 t; 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 sho gqta/8aogp3:(s d6tkwn 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 galvanomeg:q/pk 3t8a6dgtaso(ter needle in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet is b2l,it;3 ndvjheld very close to the opening of a solenoid as shown in the div3 j2l d,it;nbagram. 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 because of the induced current?

  09.37: For the figure shown, the variable resistance in q 1y; llsk1.lnthe circuit on the left is increased at a constant rate. What is1;ll 1y knlq.s 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 vm ) rkn n3-w3.hklts.nery 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. What is the direction of the force on the bar magnet because of the induced current in the s rk h3..mlwksn3-n t)nolenoid and which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of j5:7m8hths-o 7j lsdiresistive 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 linearly 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 conventiot7i5lh m s:oh8djsj-7 nal current in the right-hand loop (as viewed in the figure from above)?

  11.41: For the figure sho2anbdqm yqv/.,gojd ( w7,, dnwn, the variable 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 19+q)av hbg jzshown, the 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 loop sits ins:+p hpknn( rojbkr 85/d d;pqixc29 0 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 prn;(sdp/c : 89d+r2qjo xik0pk 5hbndescribes the result of this field increase?

  16.47: Two small loops of wire arilx8h9).qsy b2jk q4f k/z+fce located close to a wire with conventional current directed up the page. A scientist then moves the loops away from the current as shown. What is the orientation of the conv+4 2bcz) hk9/ykj xif 8fqsq.lentional current in each loop while this occurs?

  17.35: A metal bar is moving to the left across a set of frictionless conductingivvyxc(d924d8 zuh i9 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 the resistors and the relation between the magnitude of th 9di2d(i c9h4yx8vvuz e currents through each resistor at the instant shown?

  08.50:. An infinitely long solenoid passes through d7 1mttlc50aj w:7bhorxa11 f the circuit as shown. The magnetic field of t1mt bw1co:aa jd7h5f7rxt0 l1 he 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 n5i6jbr6 )jzhsjrr9 s,)i(epis decreasing in time. A constazb,6r5jr9re p6sh i) )si(jjnnt 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 voltmeter connected to the corners through the center of the loop. What is the magnitude of the voltmeter’s reading?