94.20: A magnet is dropped through a vertical copper psap1 n1)n g1:z8akn pkipe slightly larger than the magnet. Relative to the speed zsank p1nn:kg)pa811 it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the di*0m efsb7l ;plrection of an induced current in a conductor by a magnetic field could be a restlesf7p * ml0b;atement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is equivarvs,z 2xsj+j:eq ;i j.w8frr2lent to srqx wi; r ,+2.vjjfsrzje:82which one of the following?

  04.34: A square loop is placedow 74 typgz56t in a uniform 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 strength of 45ttz wy6p7og2 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 eh*c/u2ajqmr:9z2 x or+tf z/through a magnetic field directed into the page. The wire experiences an induced charge separation as shown. Which way is t t+m2u *2/j fqzz9x /re:oachrhe wire moving?

  00.20: A wire moves with a velocit7vh arf (z)vwna w(yer6; ;he2y v through a magnetic field and experiences an induced charge separat6w( y(f72a;hhav er rwvz)n;eion as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on two 7p66r(vpxhrn 14wrnb conducting rails. To make an induced current i in the directrbn6x6471prrpwh( v n ion indicated, in what direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field has a voltage indg*hqng,40 );kvc hwm4qmhm8buced between the wire’s ends, tk m,chg)qw4mm*;vnh0qgb84 h hat 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 velocity2umxt6gf4a0gxqocw h)4qw p. g 1v4i+ 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 induc uqq ax4f) ig g4+wm 61hx.tvpo420cwged across the rod’s length?

  04.42: A solenoid is oriented end-ov ss;x v+2tudw2p0d k2n 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 negligiblep skxv2d2 vtw;u+0ds2 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 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (which are assum2qdaxyfk4 3fv+i -p 2f*fy xd+ed to be close to each other), the resistance of the left-hand circuit is slowly ivqf*+fd23fi fa p-xyk 2+y4dxncreased. 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 opening of a solenoid9 ,fxn3z5kw;t0 lcz5bl,u no d as shown in the diagram. As the magnet is moved away from the solenoid at connd fkz9bwo;z0 c3t,,lnu5xl 5 stant 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 wv.2cfgz81 sm :xz5rcresistance 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 what direfzsr5c m. xw1:8gzv 2cction 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 a s p-r4ulm4dej*adgs)vn2 rl 5f *s5tt5olenoid as shown in the dia ud dvf-4)5 rml5n2gsr**st4tpe l5a jgram. 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 solenoid and which magnetic pole does the “??” in the diagram represent?

  14.34: Two circular loops of resistive wire are placed next to en re9;l2a ,eedqm3j6sach other as in the figure. The circular loop on the left is connected to a constant voltage source V. The resistance ofeq ls n m2dr6e,9ej;a3 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 right-hand loop (as viewed in the figure from above)?

  11.41: For the figure *rq2x b 2joq: jkt8 ,dhto/hw1shown, 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 shown, the variable resistance of thrwtce8x5; e0 -cc j v1*a/ynwue 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, conductinl/r2cme (w -* uofzh5ew ie.j.g wire loop sits in a plane perpendicular to a spatially uniform magnetic field pointing in2.fhe-/ ze*wol ewu 5cmjir .(to 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 increase?

  16.47: Two small loop vr+/ j6gqkoy3hc+um6s 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 c+hv/6kuyorq 3+ jm6gthe conventional current in each loop while this occurs?

  17.35: A metal bar is moving to the left across a sj66) y6kop ib5usg du.ak1n 3qet 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 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 the31.6qbndoup6 kasy k6ug5j i) instant shown?

  08.50:. An infinitely long solenoid passes through the 2*+uc*2un-)- vdxdd oq mrqeg circuit as shown. The magnetic c v g*)r2 qu- e+ddm-qn2uxdo*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 decr.u e ohrkxyd.7g1dk55 ,hwscvy8 m71 beasing 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 res8hshxd5 mkdw.c71y, g.y1bo 5ue 7rk vistance 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?