94.20: A magnet is dropped through a vertical copper pipe slightlyrce (-pqac z+(d+ j,yknrue95 larger than the magnet. Relative to the speed it would fall in air, the magnet in tpc9dua+,e y c e(jrrnq-k(5 +zhe pipe falls:

  01.30: Lenz's law concerning thm(u(iuvt 3li ;oj,( on k3h0qwe direction of an induced current in a conductor byq(kwu otiioj 0(m3hu nl(3,;v a magnetic field could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/+jpa+u0st -8r d sbtt8bca 3u:second) is equivalent to whu8td8a j+ba3 +t- :cpsurb s0tich one of the following?

  04.34: A square loop is placed in a uniformv99hzt**ot f l magnetic field 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 flzt*h9o9vt* 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 z fnj*qd6 hq9fh(g*;i a magnetic field directed into the page. The wire experiences an induced charge separation as sfihdz *jq(*9gn6hf;q hown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic fiew n(pu0lrwy :+h amlob-(r03xld and experiences an induced charge separation as shown. What is the direction of the magnetic fiel l(u:p la(nrb-h +ww03mryox0 d?

  05.33: The figure below shoytx3vnsa 3os*dg 2 c9 fi/ gdmi,/8*kcws a bar moving to the right on two conducting rails. To make an induced current i in the direction 33cdit 2 knvc fgdg8/imsyxso /*,9*a 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 t 5x*2 ricu * sv w0hn*6rdkrn7d)k5yfhas a voltage induced between the wire’s2 0hkti*c7ur)5 *rvfrd *nyskd5n w6x 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/hdg .kx7n :bd constant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T.:h/ bndd. 7gkx 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 openingc at3:f21 geo*onqc;k is perpendicular to the circuit contaieco1g :3kqa fcn*t; o2ning 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 to dimmest.

  07.34 For the solenoids shown in the d i(g 2ozvqx5o:j hc/3yd ff85qiagram (which are assumed to be close to each other), the resisyf/vfg 8xqo(c5jh 5o3 2di: qztance of the left-hand circuit is slowly increased. In which direction does the galvanometer needle in the right-hand circuit move in response to this change?

  08.29: A strong bar magnet is held very close to the 5 y cgvl6 xpfi b l3u2bhyl37ewlry)0x+;st8 7opening of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid at constant speed, what iswvtgy 05 lxl3yx86b fu)+2 hy77ils lp;eb3rc 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 on .prbs)xbci y9 c4w3k4the 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-hand circuit?b ycbckrs39 xpi4) .w4

  10.39: A strong bar magnet is held very close to the openc7v-w3a 1vnpk t3 *dwsing 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 t1pw33vn tvcd-*wa s7khe 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 t9kg3upwi0mposx 7grb. m5s+2os42woo 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 s 2mo03kx oiu s7owgp pm54+.rws2g9bis 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 s f:kmsjx q-s9 sno *;v;,skk0resistance 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 resistance of t6q *q;my; n0 fml7jx pk+ad;okhe 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 perpendibhe )t4q7tn ;jctq:8g cular to a spatial t;nh7gtjq e4b8qtc: )ly 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 result of this field increase?

  16.47: Two small loops of wire are located close to a wire with conventionat0* t .h/qmiodl current directed up the page. A scientist then moves the loops away fromod* t./ t0qihm 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 tcc elhg2ubn+0:rl 5c ;o the left across 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 relation between the magnitude of the currents through each re e:bcu;c gl2ch 5n0+lrsistor at the instant shown?

  08.50:. An infinitely long solenoid passes through the circuit as s db q 58l/w.u:cnjzl+ehown. The magnetic field of the qc d b:jn8lle.w/5zu+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 them-tx f 8yzyz5j*-p8 mj/ajgpdvg 08j5 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 ojmp*z dmj0-j88jy85 - xzat fp g/gvy5f 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?