94.20: A magnet is dropped through a vertical c2vx9 5u9ptsbgopper pipe slightly larger than the magnet. Relative to the speed it would fall in air, tv 2g9butpx9 5she magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced current in a conductoro gst:pkne3-u. j/ 4x8c uzk6s by a magne-n:x/tcuks e pus34ko 6gj8.ztic field could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is equivalent rt;)5+k/y1 c ow:snn- ufwartto which onew su:anoyr)tt5k cf/;+-1rw n of the following?

  04.34: A square loop is placed in a uniform magnetic field perpendicular to the gtnr tn:+k8zd5j0 z9n 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 +grz9jnt : n05dn8zkt 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 dire, )lt:wo:irg octed into the page. The wire experiences an induced : t), o:rolgwicharge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and experiences 51 oxs8 9l(b he.hbbagan induced charge separatio5b sbb heh1l( g8ox.a9n as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on t:nbtznr as(m6p 3i 3-fwo conducting rails. To make an induced current i in the direction indicated, in what direction would the magnetic fiel- :mzft3pr6n(bain s3d be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic.vzkk6vd p*n* field has a voltage induced between the wire’s ends, thvn6*dk*pk . vzat 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 m/s trav: , lf; oszyw1zlkq)1v fol.z (x)8kbbeling through a uniform magnetic field of 0.060 1f):;vs1b.zf y zk)ql (bok,llozwx8T. The rod, velocity, and magnetic field are 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 is perpendicular to thr:gahp /:s sx)rf *iwqyc5 3:ze 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 brightest toryci:53:gwa* s/ s) fhxzrp:q dimmest.

  07.34 For the solenoids shown in jxi3acrw2opg90;)w x 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 resa0i owp3c92 x;w jxrg)ponse to this change?

  08.29: A strong bar magnet is held very close to the opening of a solenoid as;d02iwvh ae ocl2z s2b/ ox;hgm)+ 3ix sh)dhl;2 0izh;si/a+xwomo3 x2c2evbg own 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?

  09.37: For the figure shown, the variable *7u 1n(wy wiwy )dkh ec6y lc796e+6;xwwoqpv resistance 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-hand circuit and in what direction is the conventional current through the resistor in the right-h* )eo6yvwdepn6qkyc+uwx(w9;h yil 7 c 6w71wand circuit?

  10.39: A strong bar magnet is held verzqf2u,*q t,c t6c tt)lpz;dt9 azbd:/y close to the opening of a solenoid as shown in the diagram. As the magnet is moved to the left toward the solenoid, a conventional current through the resisto, 6z2qt9b udz:a)ctqtld*,zct f/t p;r 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 other as ,bemrospa2q5,t ex+hhn zr n3b61k/(in the figun qotr bn,r ah e,embzh /2(1kp56+x3sre. 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-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 r )m0zb grd8w3zesistance 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 resistancv5u4c9nz b gthg5/ 1ute 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 pl:mkgmxlmd ;g)3at0ml5(e06q.tyodon5 1 fwire loop sits in a plane perpendicular to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field strength steadily increases with timaop1t) gmql (k ;yd3m60:5d x0n5tmm.e gflloe. 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 a4/fs, vnis/stjp2 l2qu1n3 zn wire with conventional current 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 loops,utv zn23 fi lq sn/n/2s4j1p while this occurs?

  17.35: A metal bar is moving to the left across a set of frict 8 nazx) ddv9tdq7+mn dd(nx8.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 resistors labeled X and Y are identical. x)8mz(td9+ dnda8vnn.7xd qd 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. The ,n0(k- a kdysvl1qj+sr k57i wmagnetic field of the solenoid, directed int, rl1kqsnak+s5kivdy w0- (7 jo 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 into4tyv7gbs yf3xq; 7sw 9 the plane 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 g7 vs4x7s 3qyb;9ftywan ideal voltmeter connected to the corners through the center of the loop. What is the magnitude of the voltmeter’s reading?