94.20: A magnet is dropped c .byy5e:5gr;y ucmtwmk 9o ,;through a vertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, :ck5g5m;;ocrwb. ytmyy,eu9 the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced czd+j-ft:qz0 hurrent in a conductor by a magnetic field could be a resdzhzt+f0q- : jtatement of

  11.25: The product (3 Teslas) × 8lk))qol n*la (2 meters) × (4 meters/second) is equivalent to wol ))qnkal8 *lhich one of the following?

  04.34: A square loop is placed in a uqza2at(vd k, 2 6dxyq3niform 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 2 T. If the loop is rotated thro23vyz6q2a(xt k, dqad ugh 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 q(t(r t hcp9geb 2b8.dinto the page. The wire experiences an induce(9bc2d.tgtp b 8re q(hd charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v througho3)4r7 i v3m,xj;qrsf iprua+ a magnetic field and experiences an induced charge separation as shown. What is the direction of the m ,af3x43 +or7 v;jpqi urms)iragnetic field?

  05.33: The figure below shows a bar moving to the right on tqwz+x1mu ;r *zf2 ll97wpkg:awo conducting rails. To make an i9r p*q+l:m w;uxwl fzg17k2aznduced current i in the direction 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 induced betwr7sz)f ok4b g.een the wire’sg7ob.sz frk4) 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 r 2+0jh, bhdzs8dtfvs3od has constant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually per bdst,+ hhs2jfz d38v0pendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is ori,ed*f;e; *bxrj zt 3nh: /j6aytq(sxiented end-on 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 f*3(n xtxyj6; rt/, iq: hajz*; sebedresistance 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 assumed to bej(uvg1)c fz9rc/nl s hjbs*-, close to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galvanometer needle in the right-hand sc c9z*bfj(l -g sn)rj1v/,uh circuit move in response to this change?

  08.29: A strong bar magnet is)7hzd7 dypcq8l 0cfq/t8)kn p/o8j gq held very close to the opening of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid at constn)z 7kp7po q l/88/cqhdy)ctqg fj8d0ant 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 resistance6 dl jzev,;w3nxi,l f,s1jqa( 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 circze6qvi3 lxn,,( 1jl;as jfdw, uit and in what direction is the conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is:j 4vp7 77zivpgzwdm9 euqi50l 6y1v j held very 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 throughj:z w7ile7im6z1 5pvju d0 q7y4 gvpv9 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 each other a ile)u 4gq(xf.s in the figure. The circular loop on theg.4 ) fuq(liex 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 right-hand loop (as viewed in the figure from above)?

  11.41: For the figure shown, the variable resistance of the outer circs aw,1o wtq/-uuit $R_{inner}$ 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 2pfblb3)i670xtspg n .a ahi7kb ,c4rthe 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 perpendyrn2a *1s+bexc s,9l dicular 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 describe*sd1 x29b ,+csyr nelas the result of this field increase?

  16.47: Two small loops of wire are located close to a wire with convention81x 1t voho ,8cnu)bwtal current directed up the page.to,18u8vn w1h c)to bx 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 set of frictionle5/xft w, ty 20lf2hbxuss 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 the2b,h utw/5xlf 0x2fyt currents through each resistor at the instant shown?

  08.50:. An infinitely long solenoid cz 1n )39vr(zktipy2 opasses through the circuit as shown. The magnetic field o2)1cito( rn p9zv3y zkf 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*k dbzo;3up 7i 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 ; 37zdibo*p kuthe loop. What is the magnitude of the voltmeter’s reading?