94.20: A magnet is dropped gbuyyf1o/u sk:a .4-psq 6 tbn9+t1 wethrough a vertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magnet ogwpebfuss- ntb 1tk6y+:.9 y1/4auqin the pipe falls:

  01.30: Lenz's law concerning the direction of an induced current in a corrr(8vlarsf;r zwjx :- *3 jb(nductor by a magnetic field could be; r*l(xr- 8s3vbjr:rr jzwa (f a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is equivalent tg3.d-iq q;bz so which one of the followingiqq.- sg;d3z b?

  04.34: A square loop is placed in ar sggkl1(6 0k*h1ppub.7 tr/zzo6dq m uniform magnetic field perpendicular to the plane of the loop as shown. The loo1k6do gz*pz.t7rlhpbs0/ m(rk6 1ug q p 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 mf 0x8dpvk1b5 8cotq1aagnetic field directed into the page. The wire experiences an induced charge separation as shown. Which way8p0vb15 kdfc1oqa 8tx is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and experiencew2phkqhvd1oz3 +)-bq(-jo-ohrtzt 0 s an induced charge separation as shown. What is the direction of the magnetic field?ow3ot -r h01to+dhzv2q hbp(-q kz-)j

  05.33: The figure below shows a w:o3e nzl.6 icl w0p+ 7xcwp-r.nn3npbar moving 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 arep.wznln0 3x+wi c oe6n npw 7c:r.lp-3a contained within the conducting rails?

  00.10: When a wire moving through a magnetic field has a voltage induced bewwgvc7 dxb*f*c m1xphzh: .1f bc7(m(tween the wire *mdh :vz (gwfcc *mfbcp7whx 1b(71.x’s 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 rodjqdflpya*8 , *ofytf/42)j m,oc ydb9 has constant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field ,8)j*oflpay fj,c94 /md tod qb2*fyyare all mutually perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its opening n 361t8wdiefetc2h 7zis 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. Rh8c3f16ze7n2di e ttw ank 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 :in:c(mef gs z)ua7b3to each other), the resistance of the left-hand circuit is slowly increased. In which direction does the galvanometer needle in the right-hand circum i:b( g 7usace)f3:nzit move in response to this change?

  08.29: A strong bar magnet is held very close to the opening of a solenoid as s i.ku-u nt4y0tj5c:el hown 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 of the force on the magnet because of the induced current? 0 lcnu4.-tju:k5eiyt

  09.37: For the figure shown, the variable resis::8xj0 gccm igtance 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-hanixg :cm8c:j0g d 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 solenoid as sl7z:v3s nzz ,2.ux pjwhown in the diagram. As the magnet is moved to the left toward the solenoid, a conventional current .,zxl3j:nsz7vu p w z2through 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 0pjtuspfi ,8z 6t5ex pmp8p41to each other as in the figure. The circular loop on the left is connected to a ptzjxtsp, 5m1fi4ep8u 68p 0p 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 so dnuu /w.m 16,q7zytw7hd/ jihown, 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 res,z occ/ 18wh- duwn hv1nu3:cdistance 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 planexw k 6r l/zv1e9.wzm8p perpendicular to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strength steadily incre/9 vprk .16ezzx8lw wmases with time. Which one of the following effects best describes the result of this field increase?

  16.47: Two small loopyg ,ihr wnbd;7 qr,,*hs of wire are located 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 the hi *nyhg7,,rb wq,;drorientation of the conventional current in each loop while this occurs?

  17.35: A metal bar is moving to the left across a set er/ hks. gmb7;m91exr9cer 46iyk2axof 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 6x99 sr k1;ik r 7cm4b/e g2hye.xrmaeY 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 shown. oo(6 + +q+plovzq cl9z3rf-pnThe magnetic field of the solenoid, z3lq p(+c f -9oon+vlrp6z+ qodirected 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 the8 8d9d j.uznzi8xfj)s 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 tznujd)j idxz898f.8 she loop. What is the magnitude of the voltmeter’s reading?