94.20: A magnet is dr pvewds)baej(4f:3je1o: 2 r iopped through a vertical copper pipe slightly larger than the magnet. Relative to the speed it w1e3bs4owdevfr2(j: a ji:)p eould fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced current in a cond (0-sfwp s7*0 +mebyt/npfjvh uctor by a magnetic field couldvf/s msb*tf-nhp+(pj 0y7ew0 be a restatement of

  11.25: The product (3 Teslas) × (2 mete+mk(q:1sug y k6 zt9hkrs) × (4 meters/second) is equivalent to wh:9 mz kys16qk gkut(+hich one of the following?

  04.34: A square loop is placed in a uniform magnetic fieldlt,3o 70aa kw3,tzu aq 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.kzo, qw0,ltu a a73t3a 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 the pag5,hhn:ew :qj;f-j dy ke. The wire experiences an induced charge separation as shown. Which way is the wire m-jqfhyk h,::nw5dj; eoving?

  00.20: A wire moves with a velocity **2ixbt wg2)hisffs c50kq/k v through a magnetic field and experiences an induced charge separation as shown. *cq0gsi2*k) / xfb5 2kfihwstWhat is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on two coffx+ueu-g a-vz)(z ) jnducting rails. To make an induced current i in the direction indicated, in what direction would the magnetic field be in the area contained within)e-ufz+ xu (vj -gza)f the conducting rails?

  00.10: When a wire moving through a magnega cw* :za-tr4tic field has a voltage induced between the wire’s ends, that voltg*a:trzwa -4c age 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 travel :em /r.ga5fbby5z1sr ing through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potential diffa1 e5z r5: f.msbr/ybgerence induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its opening is perp2;+r7 u)wm dwg.cdx acendicular 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 magneti2a) urxc; dw7c.dmg +wc 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 sdjzb ,1 (xol;5rl0c 5:na tnsjhown in the diagram (which are assumed to be close to each otherjb ;tacljn d 5,:x(o s10lzrn5), 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 change?

  08.29: A strong bar magnet is held very close to the opening of a o,fd.)(zu hb 6hbd3omsolenoid 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 shown and what is the direction ofhufoob6.(d)m hb 3d,z the force on the magnet because of the induced current?

  09.37: For the figure shown, the variable ref2 c5ly3t49 fd8lga3n;tij dro9von) 13ave osistance 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 centeeo5odl t8vifn2vl39rdn;3 o)ca93 tf gj 1 y4ar 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,k 51iah3 fxu3 qnczm4 held very close to the opening of a solenoid as shown in the diagram. As the magnet is moved to the left tc,xz51fmk43 qn ui3 ahoward 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 eqy zwggsw- 6d6w2ox6 -ach other as in the figure. The circular loop on the left is oq wxzy ggs-d66ww62 -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 soqbx*qw*/*xa8 f x; rcircuit $R_{inner}$ 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, tkp+srbi643q55vas ase0au 6 )dk /ydq he 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 loop sits in a plane perksy8:(d4mc9n -nov.fsk e a7ependicular to a spatially uniform magnetic field pointing into the plane e4d7y-k v.saf8:k ennocm (9 sof 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 conventiona09,)jtzyp pw0uj 9z r./vm amll current directed up the page. A scientist then moves the loops away from the current as shown. What is the orientation of py ,)j raujl0m09zt/.9w p vzmthe conventional current in each loop while this occurs?

  17.35: A metal bar is moving to the left across a set of frict ri4: /x5vdzp+j* axvuwrc )j/ionless 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 resistoirv/*+ vw )5aj4rpd/ xcxju:zrs 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 )q2r8sgku c.lv,8vhp6m: d+lezv+t wcircuit as shown. The magnetic field of the solenoid, directed into )+rv t,uw. c2 lpv8 8ge:z6mk+dqhvsl 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 zp.mptpcp,,3 gw/x:p;1xt ie 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 light bulbs of resistance R in it and an ideal voltmeter connected to the corners through the center of the loop. Whati1p;pwpgx:tp .e, x/t cm3zp, is the magnitude of the voltmeter’s reading?