94.20: A magnet is dropped through (lgh2q z;;xj/ sr) cpza vertical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magnet i2/zh;lr cx p(jg;zqs) n the pipe falls:

  01.30: Lenz's law concerning the direction of an induced current in a condu,pebo3 cflp +3ctor by a magnetic fpl3po b+ecf, 3ield could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/second) is equivc8mh/c lq c3w-dtcqvh3.a 5c ,alent to which one of the follo l-c,d5qh/c mc8cwh . t3qv3cawing?

  04.34: A square loop is placed in a uniform magnetic field perpendicvf;9b56yw er1qrqtd 9ular to the plane of the loop as shown. The loop is 0.5 meters on a sideq9wv1ret; yfd6 b 9rq5 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 the page. The wtm6 ksl4/k9ct2 //7m6x ks6mjeuuxw.jlw 2cy ire experieneu29k4ll/.6xmy ww6jksk j6smcx2t / umt/c7 ces an induced charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a maf/u:zf1wmz6kn g 3yl7d3t1eggnetic field and experiences an induced charge separation as shown. What is thef3k ug 6ezyml7nzgt:1fd /1 w3 direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on two cond *t d(em)) cdoj--ywcducting rails. To make an induced current i in the direction indic -j -)ydwt omcdd)e(*cated, in what direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnv6ms9 l9wop 8k7n dqx(etic field has a voltage induced between the wire’s ends, that l7( xsw9k o9d 6q8vmnpvoltage 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 rodx) 6ba2qpuf q; 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 perpendicular. What is the potential dif;)6qub2p qxfaference induced across the rod’s length?

  04.42: A solenoid is orientedrna*.sm- (qqtw/lwwp j*0*k x 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 solenoiqw aw tn0kqx.p*jr- ls( w/*m*d, 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 diagram (which are as 7nj* 4.kbn aci9k;oz94 qtzjvsumed 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 rqz*c9ak.n7t k4i9n 4;boz jvjesponse to this change?

  08.29: A strong bar magnet is held very clore,r; mo 8nqtg56q yo.se to the opening of a solenoid as shown in the diagram. As the magnet is moved away fro8.yo tq5 6nqmrrge; ,om 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 circ un 1fj(xa3nbp3/a(a muit 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 convention(f /a3bnaumxj(p1 a 3nal current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is held very c wf8)b0qsvj ,llose to the opening of a solenoid as shown in the diagram. As the magnet is moved to the left towafvwj q)0 bs8l,rd 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 zlnzb*0 q qm8s6:t gtm95(a/ +igfa rkplaced 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 point P (the centesm/50r8 6 azqkgl(b:ga tq n fm*i+tz9r 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 resistance of v6gwk/*h+w- lvr0 2q9zvfkw sthe 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 resisp9;u:r; hlumc-5qw44r iipz ltance 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 s1jj2,x ck) jrmpatially 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 the result1) 2xrjj,j ckm of this field increase?

  16.47: Two small loops of wire are located close to a wire wisse/i *-0jadimp) cdqz*7uc 8th conventional current directed up the page. A scientist then moves the loops away from the 87p*)sd m uieiq a/c-czjs*0dcurrent 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 friction1-z-vkza,gob*tnb0 f yr.rk 6 h8(t wqless 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 relation between the magnitude of the currents through each resistor at the insbb 0oz r r8g-*avwqynz(h-t,ft6.kk1 tant shown?

  08.50:. An infinitely ln.9u4 w4nyvj hong solenoid passes through the circuit as shown. The magnetic field of t49vj. nnwuy4 hhe 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 t pvtg0+b09b qyime. 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 v yv g0+p0bb9qtoltmeter’s reading?