94.20: A magnet is dropped tulc;vo(jpp . .t)t pc,hrough a vertical copper pipe slightly larger than the magnet. Relative to the speedup(j .cplc,o v.;ptt ) it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an indut 6 13eb hj/zbkkhng;al.*9dpced current in a conductor by a magnetic field could be a restatement 9h tlkghbj eap 1*3b ;/kz.6dnof

  11.25: The product (3 f)ze-5ax jkj 3Teslas) × (2 meters) × (4 meters/second) is equivalent to which one ojzkf-x)53a j ef the following?

  04.34: A square loop is placed i9 jlp;f+po bc-q lhd0:1ajv, in a uniform 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 through an lfd-1vp :a;qo+ ,jpbc09hli j 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. Thn0 c 7n+ctngl1e wire experiences an induced cha 1 c0nlgc+ntn7rge separation as shown. Which way is the wire moving?

  00.20: A wire moves 4:h ju1 htnhhqyg d167with a velocity v through a magnetic field and experiences an induced charge separation as shu1:q7 j 461nhh dyhghtown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar 2o0yba0a*lk y/4xrum7vk1 hd moving to the right on two conducting rails. To make an induced current i in the d0y h4 /myk02lou1 adxv7r*bakirection 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 mag2 t0l27q5szv* fd) au zn ;w9/wmy2+vqreuf bwnetic field has a voltage induced between the wire’s ends, that vq 25 wfsq+vmz;2*vfaurynzbt d0w9)w ule27 /oltage 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 traveling i(u:o(w lz/cnthrough a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potential difference induced across the rlu(c(:o z/wniod’s length?

  04.42: A solenoid is oriented end-on so that ij2dn k*8q9gsm. 95 mlif yn0xgts opening is perpendicular to the circuit containing the two9 0nsy*k298gmx 5fijl n gmq.d 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 qj, 95 wi(k)z*pzufg fshown in the diagram (which are assumed to be close to each other), the resistance of the left-hand circuit is slowly increased. In w(if,fj9qw kuzp )5z *ghich 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 opening of 0de-t0vxg pl+:s7 jsa 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 tsg pd-0xjvlet:s7 +a0he direction of the force on the magnet because of the induced current?

  09.37: For the figure shown, teck 7 q o8l7zroth9:nwvn l62-he 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-han 92ot o8q67rc7zn hwnv:lk-e ld 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 the opening offlw k(gf7s80z t-t j3d a solenoid as shown in the diagram. As the ma03 zst 7gk f-twf(ljd8gnet 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 does the “??” in the diagram represent?

  14.34: Two circular loops of resisti5*q0dbb5r9u tjt,yn fg;i02b- w1kiyk (iyaeve 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 point P (the center ofdik1 i9 jrty *a0;e0qwi(, 25bky fuby -tb5gn 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 variablx (wp u-n82whme 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 resistance oape e.kz;z(nb 9gsw s5 bk5m3;f 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 e8yzh) e.:w w gidm:hc92a:stsits in a plane perpendicular to a spatially uniform magnetic fie. ye:9e8 a::cwtizs 2 mw)ghhdld 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 locatedl8 9ub ndv(3rfz mb/7p 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 ofnf7bdu9bp3 rlvm(8 z/ the conventional current in each loop while this occurs?

  17.35: A metal bar is moving to the left across a set of frictionle,kyk5 rp6-i(tpo :yff;grx 9qss 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 tyk6f,py9gp5i:-r qxor ;f k(the resistors and the relation between the magnitude of the currents through each resistor at the instant shown?

  08.50:. An infinitely l 6cc a1oxn,du,ong solenoid passes through the circuit as shown. The magnetic1cuo6 n ,,adcx 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 th e mfij8ahz;jhg9, k38e page is decreasing in time. A conf9jj 3;zm8gkaieh8h ,stant 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 voltmeter’s reading?