94.20: A magnet is dropped p /vxioes2s9 v8-u sm*through a vertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magnet in the pipe fall 8 vsox/-vs29iep* umss:

  01.30: Lenz's law concerning the direction of an inducw(:qwm7 vny: ccl,d-wed current in a conductor by a magnetic field could be :mww cvqnl(-,d7 y wc:a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 m4 mm6qvu1nih yz,61a beters/second) is equivalent to which one of the foq 6mi , 14anmv1z6huybllowing?

  04.34: A square loop is placed in a uniform magneticn n ,j,)fvl)pj 0;zyox field perpendicular to the plane of the loop as shown. The ;,vy)zfo) jj n,0lnpxloop is 0.5 meters 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 th ko+ 6 :gnwk/szycm3f.e page. The wire experiences an induced charge separation as shown. Which way i.3mkz+ 6 /kcog :nwysfs the wire moving?

  00.20: A wire moves with a velocity v through ap, m:mi:uj24xip*zc2um g ck, magnetic field and experiences an indux p:pgm m i4cj2zu2, i,*k:mcuced charge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right ony*uha 1,rzs 1u two conducting rails. To ma u1*rahzy,s 1uke an induced 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 hdf r - meg)+k9uqdy2b2as a voltage induced between the wire’sbkmr9 e yd+q22 )gfdu- 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/s t a o6aphaup :*x0bl6b(c+j 1dobhk rk2+0+b hsraveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potential difference induced across the r a*o abb:b+sx62ah pdulop( 0kj1b+ cr0 6+hkhod’s length?

  04.42: A solenoid is oriented end-on so that its opening is perpendiculi 52k 2k8dos/ v soy.jjei )vhm(.f9c ay.fsw9ar 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 thsda2)c8 99yh5 iwe.skf .o(2sj/v j.kifm vyoe 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 be close to wkzhy8jw0n5ukomz5q q0oc * 6)p-e0z(kpnt- each other), the resistance of the left-hand circuit is slowly increased. In which direction does th5)00o mq0z-8kqn5 *pjpnkzotchu yw6-zw ke(e galvanometer needle in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet is hel:7zu:f z n;leab+hny0o 0pg(ld very close to the opening of a solenoid 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 fyh:ln0laezg7p0(b+z;un o: 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 ri 7/;2bkyol1gsls4c i: i wg,zesistance in the circuit on the left is increased at a constant rate. What is the direction of the magnetic field at the po4w7gg b1k iiclis:o2y,l sz; /int 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 i0x+ vi+i .xcm:frvv q6bbcc 21a75+u(s tpwm 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 through the resistor shown is directed from Aw5ac+x. rm v+c uip:ic7fs12qm 6xb+v(b 0ivt 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 resistivbcsq ,d 1 a-rpl1fpjc,wh/0cwj4xj .2pve j27e 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 linea-r 2,2.pcxcjwp wec1v4sjq jlh/ pfd,j7ba1 0rly 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 figur6 1tzis .k:mybkc/:fpe shown, 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 )9mhatq0)p sd 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 pe .6swks djz3q3rpendicular 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 bsqz3d3 .sj6kwest describes the result of this field increase?

  16.47: Two small loops of wire are located close to a wire with conventional cg cz:j,v.nsbbd u(-zrq-ueu*8y dz*4 urrent directed up the page. A scb8u :buy z- 4cd.gd,uze-*r sjzn *v(qientist 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 accud :4tf4v dkk2y.8byross a set 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 conven4bydtc8 fy:k u .vk4d2tional 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 passes through the circy 6nhhb1*nqif (vj7xa+d ++dgc.vrs4 uit as shown. The magnetic field of the solenoid, directed into t*xr djg4hc(dn .v+6 qavyibh1 fn7s++he
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 dirw ;34 jf19 ljjq.hhulwected into the plane of the page is 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 ligh h;u9wq1h4lfw lj.j j3t 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?