94.20: A magnet is dropped through a vertical copper pipe slightly larger th l54r.;padl mtz 3sh4,uc.axzan the magnet. Relative to the speed it would fall i;.mz4ur 4dspall zt hx3,ca.5n air, the magnet in the pipe falls:

  01.30: Lenz's law concerning tr7n 2-wb:-o)vixyqg( led p9 pt3aib;he direction of an induced current in a conductor by a m (;obnbiep g pt-yil73:wa-vx9dq 2r)agnetic field could be a restatement of

  11.25: The product (3 Te4oj*but qn,7+byccx0go : oo *slas) × (2 meters) × (4 meters/second) is equivalent to which one of to4ncb0+o:7 j c**gyobo ,tuqxhe following?

  04.34: A square loop is placed in a uniform magnetic field perpendicular to the(4*2oy lld jemlkjy; f:40mmh p4f0; 2ml(:j4eml*d jlhyymo klane 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 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 magneka 4-x c(-wu.rrba.vm tic field directed into the page. The wire experiences an induced chak.a4bwxcvm. - (aur-r rge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field and experifauu1px+nawx.b2 tnqn9 01d/ ences an induced charge separation as shown. What is t2and1np/0nfa qub9. utx+1x whe direction of the magnetic field?

  05.33: The figure be op*zg8uw3 *8tn givg. gpm4j/low shows a bar moving to the right on two conducting rails. To make an induced current i in the direction indicated,3puv8 *mg.ojg*pgt/n84giz w in what direction would the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magne 6ypi +)uq-tsntic field has a voltage induced between the wire’s q+p6is-t )u nyends, 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 coryq ter*f6m025gn f-0b )zcthl+gj* tnstant 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 differt nf0 tbhtqmr-e0c lggr6f)+5 **jy2zence induced across the rod’s length?

  04.42: A solenoid is oriented end-on so that its opening is pv 8bnwf4q y4z7erpendicular 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 time at the same rate for each circuit. Rank the circuits for the brightness of thevbn7f8zqy4w 4 bulb labeled R1 from brightest to dimmest.

  07.34 For the solenoids shown in the diagram (which are assumed to be close to 8(wt8amk6 rpaarm ,e 0ae7uo3 each otherk aaa,8ua0 r6wm preoe7 mt38(), 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 this change?

  08.29: A strong bar magnet is held very close to the opening of a solenoidf/n/)vms 1)euvwj ws ( as shown in the diagram. As the magnet is moved away from the solenoid at constant speed, what is the direction of conventionaes)uvn w/w m/ vf(s1)jl 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 sho,a5og qef:vda f4ug 7/wn, the variable resistance in the circuit on the left is increased at a constant rate. What is the direction of th fd aqeu/ ,:4fg7o5avge 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?

  10.39: A strong bar magnet is held very close to the op vb 65(s)ne a4mn,knsxpd (h*rening 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 dirs px(ven)hs46n(*,n ab d5rkmection 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 placed next to each other eze xzw1osmy+d0:b+9 as in the figure. The0ywzbe9ed:m o +1x+ sz 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 above)?

  11.41: For the figure svp8elo1v;f a ncz8.f8hown, the variable 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 of the innerci:l qh9gxazahy-r1 ,-brcuit $R_{inner}$ 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 tj+zzm0+ux5 (eu s h5ffo a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic field stren0 +e5fx fm5(juhs+ uzzgth 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 conventional /9 52i xugg0xpuqw:zj current directed up the page. A scientist then moves the loops away from the current as shown. What is the orienta xip:5g xw29jgq/uz0ution of the conventional current in each loop while this occurs?

  17.35: A metal bar is moving to the left across a set of frictionlec8;t ) ez3vdfess 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 p8dtv 3ee;zcf) age. 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 instant shown?

  08.50:. An infinitely long solenoid paswbvmb:/4x qemv* u*/e ses through the circuit as shown. The magnetic fiemb4 / *w*eve/bqux:mvld 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 insu;h47aktm7 bu k9e q4to 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 k;etuhm u49477 q akbsthrough the center of the loop. What is the magnitude of the voltmeter’s reading?