94.20: A magnet is dropped through a vertical copper pipe slightlo1nvh t+b: *k* ubyyp,y larger than the magnet. Relative to the speed it would fall in o ukb*yh+b:1y*,p vtn air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an induced current qgf3h1dle 5k7v vkp03in a conductor by a magnetic field could be a restatement of1d efl3kp 03hvqv7gk5

  11.25: The product (3 Teslas) × (2 meters) × (4 metersbu 5)hejlak +gmt+c67+ s*kuncb8d 2d/second) is equivalent to wh cebk+ jk8na26g 5ub d mt)7+h+dsuc*lich one of the following?

  04.34: A square loop is placed in a uniform magnetic field perpendicusvuj.-j/mx.xs2 an 9blar to the plane of the loop as shown. The loop is 0.5 meters on a side and the v nm.b-s/ uas.9jjx2xmagnetic 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 thyimt1(s qaw9/o b(h)q rough a magnetic field directed into the page. The wire experiences an induced charge separation as shown. Which way is the wire movia(qh91ow t y/)im(sqbng?

  00.20: A wire moves with a velocity v through a magnetic field and exper f(fn1/ nvfwba jwl(3*k)ig h8iences an iwf(wka 3n8n(lbf*jgfi) /1h v nduced charge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the righ66*pjx0k zkwcl) (0htlrkv.i-q8vzb 1q 8t ugt on two conducting rails. To make an induced qrv)pjg1l6l *hzb-vck.0kit8 utx6w8q z 0k (current 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 moving through 49sn-in .tu-w / bh7cnf ,goefa magnetic field has a voltage induced between the wire’s en-4wsgn-ni f uno7h9/btec,f.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 velocityof id1 3pm ) ekse)j1w9hzu04u 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendieh0j3d4 w) mu9puk izfeo) s11cular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is orr(wgs flvp54b4vgxdmkwva y,- . 1 7r1iented end-on so 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 t 4sbdp a .wrm17r-gwxvl,5yfv41v g k(ime 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 diagram (which are assum93awkvs (h,l+*,qh , aspzig ned 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 h a ,,3g(swa+s9pkni*zh ,vq lright-hand circuit move in response to this change?

  08.29: A strong bar magnet is held very close to the opening of a sx0tn :me ezg,;olenoid as shown in the diagram. As the magnet is moved away from the solenoid at constant speed, what is the direction of conventional current thg,:n;0et exm zrough 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 on the lef*8i (tww ofb-bb( a;9jd4 iobkt 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 dirt-94;iabb(i*(b dkb8 ofwo jwection is the conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet lk kn a)c jbox+1+9ys /co+m,kis held very 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 resistor shown is directed from A to B. What is the direction of the force on the bar magnet because of the induo+ybn9+ajmk1 / + skc,ol )cxkced 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 o-x+hwglw0 n3m2bv -ug ther 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 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 abov0 wmgux-2bl nv -3hgw+e)?

  11.41: For the figure shown, the variable resistance of the outer circuitr*nb+ mcaqu:7u u2l v7 $R_{inner}$ 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 reb.o;d :: 5kudbxk6ro tsistance 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 pg yp,gp8unecy+o/8x c*t88nperpendicular 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 fo8,np*u+cc/gp8y y8o eptg x n8llowing effects best describes the result of this field increase?

  16.47: Two small loops of wire are lxvvw gf,3a 9.;fbw6wt ocated 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 6.vf3 ,wg;fw9xtvb aworientation of the conventional current in each loop while this occurs?

  17.35: A metal bar is moving to the left acroa ,sc zgfe3sa(k 7,deg h,5n:bss 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 indi s ga,da egzbn5,k:(ce,h3sf7cates 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 passn 3 r( n8;d6w4ns)uzqxuz*fo ces through the circuit as shown. The magnetic field of the solenoid, dire4 w zn*6(;dcunquf) x8zns3r octed 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 intl:.i ( ikdex;n-jyv3jo 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 an ideal voltmeter connected to the corners through the center of the loop. What is the magnitude of the vnd-vkx .:3( l ijijey;oltmeter’s reading?