94.20: A magnet is dropped through a vertical copper pipe slightly larger te-a va4gso ;/chan the e/g-oavc;4s amagnet. Relative to the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction ofcb/ n+*+t c*lj3ylzn u an induced current in a conductor by a magnetic field could be a reb/*l3c ntjunc+* z ly+statement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is equi br x9dd:e1h:+k e4,j:w qwsidy mla3.valent to which one ea x,dddb4j: r :3m1 hi.kqsl9y +:ewwof the following?

  04.34: A square loop is placed s)r-clq7 b+m jin a uniform magnetic field perpendicular to the plane of the loop as shown. The loop is jlmcb7r- qs)+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 q9;mv xn x25:l8p yfouu.hypmx ,3y)nthe page. The wire experiences an induce8n lxfno2,uxv9.3yqmppy 5xum;h: )yd charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velon4fszd.;7snpaj 28d qcity v through a magnetic field and experiences an induced charge separation as shown. Wnqjfd78sdp2 a 4;zn .shat is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on two y(yfs(w+u o 0g (mmeg8gqz/k) conducting rails. To make an induced curren(+(gg(0zs8o gmyqueyk m/w f )t 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 movin7qc2yks6 r2vd pmz, b/dv/ eh;g through a magnetic field has a voltage induced between the wire’s ends, 2yzbv,pe/hk;rvd6 2sm qd c/7that 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 consta5:cmk+ lnrz 79p wogz.nt velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. 9g: zkmrpwnz cl7+5o .What is the potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its v89nx20jk.e-n ;a b ntb+gbpqopening is perpendicular to the circuit containing the two light bulbs as drawn in figure C1. For figure; .2npv90b bta jg8b-k+xqnn es 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 brightest to dimmest.

  07.34 For the solenoids mqe8h9 +w7t)cn d0jof+mw y e(shown in the diagram (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 move in response to thismf n)9e me(oc8d t7y+w 0hq+wj change?

  08.29: A strong bar magnet is held very close to the opening of a fycky jc7z;u(sd3(va p2. *ce solenoid as shown in the diagram. As the magneccd3ay7jz 2fs (k;v(*ycuep. t 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?

  09.37: For the figure shown, the variable resistance in the k1yk lkt*g.bies+pj(0151yrt fsx o.circuit on the left is increased at a constant rate. What is the direction of the magnetic field at the point P at the centek10xk51.s( f lk+.t gy ies1orjbytp *r 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 close to the opening of a solenxyw*7 bl zdoz-:av1i (l8apn f,4lj;d oid as shown in the diagram. As the magnet isl: zy ija7b ,v*z addln-l4woxp8;(f1 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 wire are placed next to each oth1 x ln7v6zei.9a h2z8dwty c9 qqww- n37rlpt0er 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 resist9i8xn0hcrdntq9.7ew1zwwlqy- 2pv63a7ztl ance 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 s(fabr ue4altw:9cbsn5 1s-4mr 6zf5i hown, 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 -lr iw*dd)(7m1th iq;v olf,v shown, 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 loop sits in a plane perpehbfz/)s 0bcfab .x99kdny( n9ndicular 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 bf9n/bz9yh 0kd (bf.sx a)9 cnthe result of this field increase?

  16.47: Two small loops of wire are lo(cvr.l3jgtj kjf47 2pcated close to a wire with conventional current directed up the page. A scientist then moves the loops awayv2jf kpjt4lc3jr7.g ( 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 across a set of frictionless c n nh04 :dg-fyxrp-m- olb/(wuonducting 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 t-g -0:o-pw 4r(/f lunhnydmbxhe 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 passesrv)n/:8 hd w*lryp5fo through the circuit as shown. The magnerfynp* o):/wv8 h l5rdtic 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 plane of the page is decreasing in tiyk 5ar2 i.d ik2t50bqime. 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 rekib25k r0t52dy. iaqisistance 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?