94.20: A magnet is dropped through a ve+az/zq c24x7j1zy yig nv 3zh:6hgap 1rtical copper pipe slightly larger than the magnet. Relative to the speed it would fall in air, the magnet in the pipe f4h jgz:a2zy7a x+1vy6 phcgq 1n/ziz3alls:

  01.30: Lenz's law concerning the direction l*-qi q/mmu , vx+4dxcof an induced current in a conductor by a magnetic field coul-ilx /um4vcx *qmd+q ,d be a restatement of

  11.25: The product (3 Teslas) × (2 meters)o.m yz)fe*to4rg, ;;s *ssbz o × (4 meters/second) is equivalent to which one of tf sm;oot s*o;rs)z 4zg*ye .,bhe following?

  04.34: A square loop is plac9jre .ocla;w 5ed in a uniform magnetic field perpendicular to the plane of the loop as showeo.c9 wlr ja;5n. 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 magnetic field directed inpsmh2iqh/ qoi-z6)+qto the page. The wire experiences an induced i m+2i/6phs)qqqz o-h charge separation as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v t + w0jqs -fv6.vjze8pc( uhuj)hrough a magnetic field and experiences an jp8j fv(jh6uq +cw-)u.sz 0evinduced charge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right on two conductiutv hu 3/z2i(8en(sy b- 3skzrng rails. To make an induced current i in the direction indicated, in what direction w83uest k ( n-/z2rushvi y3b(zould the magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field has a voltag7 bb h:3ibohu0zo 1j1ae induced between theaob10hbo1 hz7 :jib3u 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 travelinfvis5gl v 1q-0g through a uniform magnetic field of 0.060 T.qv vlis51-f0g 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 opening is perpendicular kv53gg.zc6c d0w y i)qto the circuit containing the two light bulbs as drawn in figure C1. For figures C2 and C3, a shorting wire of negligible resistance is vdc3iy6k 0qzc.gg w)5added 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 therj.i jk,s5o i: diagram (which are assumed to be close to each othesk,ji r i:.oj5r), 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 y7k99zhw7vyobxj zox me7, fx;l z5e) 0r01oqvery close to the opening of 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 thre 1b9,r v joxe;7kzqmy0xhwy9z7 5zox o0l)7fough 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 resistan jqo d/y 7jc2nvtrrhk :+q1eak6b3)a 1ce in the circuit on the left is increased at a constant rate. What is the direction of the magnetiqkqk1no +72db1ja /:ehr)yvc3a6jtrc 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 opening of a solenoid as ibx fb n.;59b b:zz5fzshown in the diagram. As the magnet is moved to the left toward the solenoid, a conventional current through the resistor shown ii5x;9bf bzb f:.5zbn zs 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 placeeo 90b yf+q6ued next to each other as in the figure. The circular loop on the left is connected to a constant voltage e0+ e9fuobyq6 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 shown, the variable rilklff6avud/ )w, ,f;esistance 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 sgi5 y. -6qfhxhhown, the 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 s5, ri0 mdr6dxlits in a plane perpendicular 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 describir0l x,drm5d 6es the result of this field increase?

  16.47: Two small loops of wire are located close to:xu ohhrgof5h /* 6:e 9meg:jw a wire with conventional current directed up the page. A scientist then moves tj5 r/9*fh xe gegh::o:muhwo6he 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 acr t y0c2e kpufzr52m9;a.7xn hc(l6tqq oss 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 followingza;(.qck57htf02e t mlpu9 c n2qx6ry 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 passes through the circuit as shown. T)ri (elw tu (zfil/02dhe magnetic rid w tf )/2iz(e(ll0ufield 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 the page is de+aorc l 0l6evim((vi (9m+y upcreasing in time. A constant emf ξ is produced for the square loop enclosing the field in the 6yc9m( (+ui oi +le(l0 arvmvpfigure. 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?