94.20: A magnet is dropped through a vertical copper pip0c /9(v1x ty6zqno ab3yzwn6xsv;-d qe slightly larger than the magnet. Relative to the speed it would fall in airtzz6 0ycqd a /6s( wxv-3o9nxbnv1qy; , the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced current iiym2f 1y,y/ ubn a conductor by a magnetic field could u1yf2byiy/,m be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is equn)jst9 v9fnx k,f5zg k.a*d l*ivalent to which one of thvf)9 x nkdkgzj5 t*fs.nl*9a,e following?

  04.34: A square loop is placed in a uniform magnetic field perpendicular bi8shohhf g8w (3j1gr au0+j (to the plane of the loop as shown. The loop is 0.hihb h 10jwua+sgr f8 8o3(gj(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 throu0o/4f:z sf gtugh a magnetic field directed into the page. The wire experiences an induced cf s/og:zf0 t4uharge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocityw24+b1 e0fg pr*tn.by x/g buy v through a magnetic field and experiences an induced charge separation as shown. What is the direct/y0 tb.fb1x py ewn2g+gr4*buion of the magnetic field?

  05.33: The figure below shows a bar moving to the rightl,(w(6,gx u0 svlm( )lg plsaq on two conducting rails. To make an induced current i in the directio6lal(q)lvuslsg(mw0 ,(g, xpn indicated, in what direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field hasuespqh .r 04n+ a voltage induced between t.su4pneq+r 0hhe wire’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 copp3rv3n -z qo0gznr ghyp:i/ q02er rod has constant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendry3gzgr -3i:opz q0nnq v/2h0 icular. 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*abqe901wqo1kq a+ pe the circuit containing the twok 0b+ ea*a o9qwp11qqe 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 to dimmest.

  07.34 For the solenoids shown in the diagyq:y* iep4ky :ram (which are assumed to be close to each other), the resistance of the left-hand circuit is slowly increased. In which direction does theiy ky:4q* :yep galvanometer needle in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet is held very clb5 a+wzjmt0z .v l3maj meo7 ji+,*q+pose to the opening of a solenoid as shown in the diagram. As m ,p 3zojelv+w iza 0 +m*tbm75aqj.+jthe 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 resistance in the circuit on5c:e ejh up68p the left is increased at a constant rate. What is the direction of the magnetic field at the point e ph6ce5p u:8jP 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 close to t tca (tdo x;is1lj+ca1oxe( + h9gv85nhe 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 resistor shown is directed from A to B. What is the direction of5+( ; 8 ox19cxj+t a(li1n edtvghsaco 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 lm x,txovhc e+ 1aojc53o+cs7; oops of resistive 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 increasing linearly with time. As the resistance is changing, what is the direction of the magnetic field at po ccxx+v ej1 5 ,o;ma+3h7toscoint 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 ne+7 ub. 9,j or8cgyjjshown, 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 resistanck zy8 8ul7itq8e 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 perpendicular to a spatia(+bz w5e ksz m4zdxl2km9 5e3hlly uniform magnetic field pointing into the plane of the page as shown. Thzbse4 l2wxm+k3zzd9mke 55 h (e 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 ,y3f2 oqw kto2wire 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 orientation of the conventional current in each loop wk2oo ,t32yqfwhile this occurs?

  17.35: A metal bar is moving to the left acrossq yktf *4n3m/l a set of 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 Y are identical. Which one of the following choices correctly indicates the direction of the conventional current in the resistors and the relatnm /k q34tfyl*ion 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 t(pnfjioq yi5y* (( bqy) b*3omagni 5(qi3ynoyq*jb*o(f ( )ybtp etic 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 pyo +jk3hzl:ujy :3c*j age 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 c3::zu y3yok+ cjj*h jlorners through the center of the loop. What is the magnitude of the voltmeter’s reading?