94.20: A magnet is dropped through a vertical copper pipe slightly larger qp6l. je4lo uw) scn8ivae*/t 9g6dh1 than the magnet. Relatiepg lh6 jn cdq64uival/s) oe19wt8 .*ve to the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the directwx ,h gc/2as5gion of an induced current in a conductor by a w2g,scg /a5x hmagnetic field could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is equivalenth 1b83oyyoem34 9h vuw to we931ho o4yw8hubvmy 3hich one of the following?

  04.34: A square loop is placed in a uniform magneti:0ohy7fsi u0ec 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 through an angle ofsheo0fy u0 7i: $90^{\circ}$ 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 page. Theyuxj,ctn36e/ giaz 4:i .j ,ar wire exp g3a,.,:j6/e tn4zaiju riyxceriences an induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a m-gk yseej3,jtu3w. g/ agnetic field and experiences an induced charge separation as sho3g3.egsy ,uw/ et-kj jwn. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to 8q plqs ld-3hnx, ipbs-n2)qg; eq4f6the right on two conducting rails. To make an induced current i in the direction indicated, in what direction would the magnetic field be in thexi2d3qhpgs-n qq6n l -qlf4),b s;p8 e area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field has a voltt) ppvwpl :bt-2ad1 -xage induced between the wire’s envx:2 ptwpl--p) badt1 ds, 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 my75pt+uw qmd25 bcl(p/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually pe7lu25dm5(pq +cybwt prpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on sob e;gil6la2 :n 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 flb l g2n;:i6aerom brightest to dimmest.

  07.34 For the solenoids shown in the diagi f1u .fbhlix-u:ig)9 ram (which 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 mof u1:bu)hf-gxi9 .liive in response to this change?

  08.29: A strong bar magnet is held very close to thy tfdr7-tb9k(e opening of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid ayb(-ft97rdkt t constant 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,k23 jrs r025 iif chzdnnj2h/2 the variable resistance in the circuit on the left is increased at a constant rate. What is the direction of the magnetic field at the point irh0r2nnj/kif2h c2 5jz3 d2 sP 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 held very c35tc x+cf x-t.yd;ef fua8ho3 lose to the opening of a solenoid as shown in the diagram. ud533; fx+o -het8cyc at.fxfAs 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 p.,d* rille5p 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 incre5ld.,p*ir elpasing 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 variaw4kw:o75 u;,x:zx3(h u4raz y j baoqcble 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 re sa k8 m*mqgco (*azb-;tt5pd0sistance 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 perphj zhb5i4l5rs)*3ogjendicular 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 describes oi5)4jhg *5jlh sz3brthe result of this field increase?

  16.47: Two small loops of wire are losxhfpx;6t4 m bz5k 5:rcated 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 thefx5;z46hxr:5 mtsp b k 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 x,(lv fnal+l/w v 93ggfrictionless 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 tglw v (3nvxl f,g/+9lahe relation between the magnitude of the currents through each resistor at the instant shown?

  08.50:. An infinitely long so8kca3(j 6q y(j3fb icjlenoid passes through the circuit as shown. The magj (akcfj6j 3q38i bcy(netic 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 0a,)lwe+o2fk g/w5ounl;s i mfce2t 0plane 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 light bulbs of resistance R in it and an ideal voltmeter connected to the corners through the center of the )u2n swi k f2g;/atowllo5,ef0m +e0c loop. What is the magnitude of the voltmeter’s reading?