94.20: A magnet is dropped through a vertical copper pipe slightly larger thabr(d8ywhtsgs+k o) k pwka ;jf);g/ 87n the magnet. Rel (k8wf/sdk)7kyorbj+whas 8p ); gtg;ative to the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning)n;osp-uwp,oy qq;/b the direction of an induced current in a conductor by a magnetic field could be aqoy-p; /,wubspn ;o)q restatement of

  11.25: The product (3 Teslas) × (2 meters) ×)1o1 /qcrg ycv (4 meters/second) is equivalent to /q1gvyco rc)1which one of the following?

  04.34: A square loop is placed in a un)arykk/q v:2 ziform magnetic field perpendicular to the plane of the loop as shown. The loop is 0.5 meters on a side and the magnetic field B has a /kv ky2)zqa: rstrength 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 inw4.;v wy h ;dh/ki 7)4zz)auhks e1ndyto the page. The wire experiences an 7whds ynvwu)a kh.) y/izh;4z1ke4 d;induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and1 sswn.3/vz zw experiences an induced ch zsz./v1wsw3n arge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on two condtqo j7b14qkzji(,)7 ) csyprd ucting rails. To make an induced current i in the direction indicated, in what direction would the magnetic f7s( c1zrijoy4,qbqdp)t k7 )jield be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic fie(62g lzef/gtsax 9 iz+ld has a voltage induced between the wire’s ends, thfl(2et+ a 6siz /gxz9gat 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 p lr,:8 dig3;p;gr s(ycu 8eunhas constant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are:(s 3;p gulr ed8in,gpcy;8ru 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 th;d5ho 6nex hf8e 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 e6d8f xoh;h n5the circuits for the brightness of the bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (which are assqc2x7q+ ql x1gumed to be close to each other), the resistance of the left-hand circuit is slowly increased1+g xq2q ql7xc. 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 ve m 5vqs8 v10 kvbb/1tu*rgn/skry close to the opening of a solenoid as shown in the diagram.k1 ts/u5 kg1 svvv80 rmbqn/*b 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 nwr4ls;lmpj 38hh/u l3 el/ 0kresistance 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 /8w llpu;elks/j4hmrl3h n30what 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 openinj *az39 lay2eg,pv* t7t vdpb-g 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 di t9pyej t*-2dgaa*v,73 pzbvl rected 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 to each other as inc dk 2 4xiu+m/)hb9 b*v5(nbnl1mtbuk 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 conventionailnbb94+(21umt x*cm hb5 u)n/kk b vdl current in the right-hand loop (as viewed in the figure from above)?

  11.41: For the figure shown, the w-u2n-x023t od ahtun 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 shown, the variable resistance of the innex )4jrld ) ubwi+g soetb9)e25rcircuit $R_{inner}$ 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 perpen5 gg9yaz/ay 1qdicular 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 beyga1 /5gz q9ayst describes the result of this field increase?

  16.47: Two small loops of wire are located close to a wire with conventiop(h fvnaz(g,g1o8bo h 2+6umfnal current directed up the page. ogf8 f(b(+6a humphnz 1,vg2oA 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 movin.a a mg fdy9b8a/bk-fbi6+k3/v d gha)g 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 ma-8gdy/ 9m a 3+if6 d akfhabbak.gbv)/gnetic 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 solenoid passegup9w gav)do9i9 ;i+as through the circuit as shown. The magnetic field of the solenoid, directed inad) vog+ i gw9u9;api9to 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 isp7 ( we)cqjxy. 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 in it and an ideal voltmeter connected to the corners through the center of the loop. What is the magnitude of the voltmeterjcyew(. qx 7)p’s reading?