94.20: A magnet is dropped through a vertical cnm-js6j 1f( zs. yhgy0opper pipe slightly larger than the magnejhfjy.( g0s61-m yz snt. Relative to the speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concc+bfd:b gn+ n:erning the direction of an induced current in a conductor by a magnetic field cg+dnb ::nb f+could be a restatement of

  11.25: The product (3 Teslas) × (2 mk.mn gyoc:gl k0,-wc,eters) × (4 meters/second) is equivalent to which one of the followi:,mg.cc -ln0ykwogk , ng?

  04.34: A square loop is placed in a uniform magnetic fisp,dzcudbp s9 +q.h h17l )-wjeld perpendicular to the 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 an anglehd s hpd7u 1sp)-9+,jlbq.zc w 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 thlc c;xi0 ;n)e *cpvzf.e page. The wire experiences an induced charge separation as shown. Which way is the wire movingv .z;;eniclcfpx* 0c)?

  00.20: A wire moves with a velocity v through a magnetic field and ,0m, x( ztcgwfexperiences an inducw( cgfz 0x,mt,ed charge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below sho4i0wk-m0sr 3fp;k( c*eary nvws a bar moving to the right on two conducting rails. To make an induced current i in the direction indicated, in what direction would the magneticirmwn4y3a 0cv ;( -p ek0*fkrs field be in the area contained within the conducting rails?

  00.10: When a wire moving through pm lad/eem f(bb9(80 ia magnetic field has a voltage induced between t98pb/(l(d i ebmam 0fehe 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 copper rod has constant velocity 0.30 m/s t+o p;zb1,za vglb5d 8dz7 jxq:raveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the 8v5d;lop z7jx+azgz qb: 1b,d potential difference induced across the rod’s length?

  04.42: A solenoid is oriented end-on so v4 bzg 0fd4zlvg* 8oqf,0 a2wtthat its opening is perpendicular to the circuit containing the two light bulbs as drawn in figure Cdzff,0 oz gbv0glt*va 8 44wq21. 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 diagram (which are ass 0mc5 wfw/(kxg79qw2e .:4 bxns dqnxdumed 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 t(075wwdx fm e x.4xs2nbd: q9 cwgkqn/his change?

  08.29: A strong bar magnet is held very close to the opening of71s3zhgp/u sk)0dhb i a solenoid as shown 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 magnetp ih0/kz)bu1gh d7 ss3 because of the induced current?

  09.37: For the figure showi,s4wl8fd2 u bn, the variable 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 th 8bflu4wid,2se right-hand circuit?

  10.39: A strong bar magnezm+8z qmav ti27kkgxc 1(e;d1t is 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 induced current in the solenoid and which magnetic pole xiz(k t71k +2a 1zvmmq8;cgeddoes the “??” in the diagram represent?

  14.34: Two circular loops of resistive wire are placed next to eac0q47oih 3wxzcq.4db dh 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 z. d cxb7o3q4d0iqhw4magnetic 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 resistance of thehi.m-yueid722t u l+bcho 1uc;vt t.: 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, th xyf+x( n)zxc/e 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 perpend0 o4 39vjlj3zwmnt ,dzicular 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 descriz,4dz tj 33wnvjo9ml0bes the result of this field increase?

  16.47: Two small loops of wire are located close to a wire with convenxvjcj; )oa.x1mjg i46:k( qjxtional current directed up the paj j v41)xx;gjqmk j(i:.aoxc6ge. A scientist then moves the loops away 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 4z(tp t2oomw*:dn)zeconducting 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 io*2t o:z) 4wznp mtd(en 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 syo6uxmr+trx*7g9ok om (t )n:hown. The magnetic field of the solenoid, direco)r(o9nk r * t+6:oymgu7t mxxted 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 plaukvm ;6r f.e(kne of the page is decreasing in time. A constant emf ξ is produced for the square loop enclos ;kfe( vm.6ruking 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 voltmeter’s reading?