94.20: A magnet is dropped through a vertical coppern5hu1 upg8zdy paev:t 77*;rh pipe slightly larger than the magnet. Relative to the speed it would fall in air, th t17; huy*d7hag 8u5ze npvp:re magnet in the pipe falls:

  01.30: Lenz's law concerning the4v mg0s usit5+x6pqu 4 direction of an induced current in a conductor by a maq64 5x tmv+0sp4guuisgnetic field could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) i,7y urkwf fv*x q6f;v7eg-ni.s equivalent to which one of the ney- rw6xuf*vv7f7.k gif ;q,following?

  04.34: A square loop is placed in a uniform magneta6xq/rqm55 7aokv6. 8/p9 vbsrvvk fvic field perpendicular to the plane of the loop as shown. The loop is 0.5 meters on a bvs. xvo/59fvav6v5 mrp6/ akrq7 kq8 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 fi+/ion(gew3)o,cfp p+) mbif peld directed into the page. The wire experiences an induced charge separation as shown+/egif no)o3 fc pm)p,bwpi+(. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic fielpyg8, jbt,e l6y(9xpc o1 zo-+gbhfe 9d and experiences an induced charge sey1g9t j(c,o89p hb gy,-l f6e bzepx+oparation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bax t g0(x0nb f3tslmh:1dm waq+2:ni3sr moving to the right on two conducting rails. To make an induced current i in the direction indicated, in what direction would the magnetic field be in themws:033g (2b1xd0t:hlnis tqfa+mx n area contained within the conducting rails?

  00.10: When a wire moving through a magnet dt*jv;;5qnn7dub ds: 9 pfi*g:d;pwj ic field has a voltage induced between5ndgu9n jj:i*dv :tfd;* dswpq;; pb7 the 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 havb,0 a,f4cc tss constant velocity 0.30 m/s traveling through a uniform magnetic fac,tbcsv4,0 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 length?

  04.42: A solenoid is oriented end-on so that its opening is perpendicular to t0lpoh( +s7owt n6.tm)--oubr/8 *esc zpbd i xhe 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 circuwo7lbn* e6s) tro0d/.+ p- ts h pmu8x(i-obczit. 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 to zv p:xl)gao(jrp)(( g each other), the resistance of the left-hand circuit is slowly increased. In which direction does t (z(goagljx )rpp)(v: he 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 opening of a solenoi3 ia9c wotzijz*rw*,6d 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 because of the induced current? z*wtcirij,3 za 9ow6*

  09.37: For the figure shown, the var 3kpg18d7u3gh2 a cbnyiable resistance 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 gcb23 kag p18 37dynuhwhat direction is the conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is f u) cru;n cbz:fh:5(yua0ys7held very close to the opening of a solenoid as shown in the diagram. As the magnet is moved to the left toward the solenoid0(fr)7uycuzs :;u5ac:yh f bn, 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 loode9ngc.yf )dq 5qle 38h51c cwps of resistive 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 conventional current in the 1 8 qd)el5ehg59 cdw.3ccq nfyright-hand loop (as viewed in the figure from above)?

  11.41: For the figure shown, the variable resistance of t fdu,:,ot7p/ ojdo 2ughe 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 shipaw06h8 h as;,r kyn/own, 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 in a plane perpendicular to a spanqkkks(4w4 *d 5k n2ldtially uniform magnetic field pointing into the plane of the(5nk*qdk k4sn lk4dw 2 page 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 loop(k9jof +qhxjtzn8 ra2 5a 5o9vs of wire are 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 convention (rjznoja xh9+o2a k5qvt9f58al current in each loop while this occurs?

  17.35: A metal bar is moving to the left across a set of frictionless co5b ;3scw/ozfziw72+zvnr0 0h xr-rz k nducting 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 rr+v-kw3z2iz s;z / xbwz5 0hrcnr0f7oesistors 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 solenoid pxw,:g453 nhtyleke 9aasses through the circuit as shown. The magnetic fix t:wel9, an4y3kgh5eeld 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 c,get zv 4oy i9awr1w/3:gwt (directed into the plane of the page is decreasing in time. A constant emf ξ is p vr(4t w,/o c9g3w: 1tyieagwzroduced 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?