94.20: A magnet is dropped through a vertizxc7 mu)os2 fa7k00 hbcal copper pipe slightly larger than the magnet. Relative to the speed it would fall 2h 0xsz70u abcofmk7)in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced currc8 f n(y(mkk ;my9l,,vk+xe vvent in a conductor by a magnetic field could , +fk;xk9mcvven( 8v(y,lymkbe a restatement of

  11.25: The product (3 Tet *i/ ke+4 t(pvnecolfv7j8-sslas) × (2 meters) × (4 meters/second) is equivalent to which one of oestve-(+ ti87 4*jl cpf/knvthe following?

  04.34: A square loop is placed in a uniform magnetic field perpendicular to th hgt +vaf/*)6qhkr)ohe 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 )/h kqf6*h+arhv ot)gloop 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 thekb sod20.7kxs page. The wire experiences an induced charge separation as shown. W sxdo2ks0.7kbhich way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field u )r/:wfa5ep(m)/xv6 d+fjm2z oadnf and experiences an induced charge separation as shown. What is the dir jo:/adm/rwxze pdmn2f af)f)(+5v6u ection of the magnetic field?

  05.33: The figure below shows a bar movim3 -btrnhvu qu/i57q27( u0ur xo m 6m5j5xjbkng 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 the area contained within the conductingn 7b ( quq55xmr0xmju i2u5t6ouv /kbhj3 rm7- rails?

  00.10: When a wire moving through a magnetic field has a voltage induced bet:rseve k+ x/j7ween the wire’s ends, that voltage isv7 rk/:e+x jes
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 travk+xy6fx)b: l2t,g mzdeling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are alx 2gdz+lt:6,xy bmf) kl mutually perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is orieg-vw37pz.i l5 wuhxr9 ez(0 ggnted 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 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 bh g9zw0wpru.g7g i3ez( - vxl5rightest to dimmest.

  07.34 For the solenoids shown in the diagram (which 1n uwbwt: xn6.are assumed to be 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 circuit move in response to this chan1 :u tnw6wbx.nge?

  08.29: A strong bar magnet is held very close to the opening of a solen2zmgzjldmx+pi 6;a en9 ::r5uoid 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 shd+6: xa n 5ieljpmm9 g:2rz;zuown and what is the direction of the force on the magnet because of the induced current?

  09.37: For the figure shown, the variable resis bt8t8v 3j*e2. j 9 xa6qjahtf1q4iqu*dv;yb wtance 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 qetx6 y8v4b. 8t t93qfaj;d bq w*jhu*12ja ivof 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 held very close to the opening of a sod d1f 4xpvb2lk vt-xw3lp18s9lenoid as shown in the diagram. As the magnet is moved to the left toward the solenoid, a conventional current through the sl-l82b 1kvxp dwf41px9 d3tvresistor 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 twuh)dvpg22qq . c(1.dlde (bro 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-havld.e(g.2qu1whdq r( )p2bcd nd 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 figurli 3wg 7cki(fb6; stf2e 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 shouas+ps6lbq2s 5; bto3wn, 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 loofdo.7q:rqf1 tm krf51 xs+gz2p sits in a plane perpendicular to a spatially uniform magnetf:fr1 qxsrf.q +7om2t5zgd1 kic 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 describes the result of this field increase?

  16.47: Two small loops of wire are located close to a wire with conventionarxc ul+ -c*5vem o9raps3 h9t2l curret32 l9rhmr5x pc voa -c+9e*usnt directed up the page. 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 acros vx.w0lje6oiog 9 8qy6j ktg4e45 )ggvs a set of frictionless conducting r4wvyg09 lot6i4.)eo8egq g jg5vkj x6ails 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 the instant shown?

  08.50:. An infinitely long solenoid passes through the circuit as show nprm2 ghi8,1 jkt,ae;n. The magnetic field of the solenoid, n,,ph8;t m 21raijkeg 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 i.oa *kgee+yq3 s 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 theeqyogae 3.*+k voltmeter’s reading?