94.20: A magnet is dropped through a vertical copper p/b: wfejbj5(narvey5 r8 +pny/ uh4/ lipe slightly larger than the magnet. Relative to th4ey l/n(jrrn:p wy b5 u/hvbae+/j8f5e speed it would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerning the direction of an indu x*ti1d4k+gz mced current in a conductor by a magnetic field c+i4 xdgmz k*1tould be a restatement of

  11.25: The product (3 Teslas)q 9tpd-*kp 6xrf k)dx- × (2 meters) × (4 meters/second) is equivalent to which one oq -)kxfdxpp9r t6*k -df the following?

  04.34: A square loop is placed inzzd/- shqskf32 )5 j9 kcehoi) 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 j9z/e3k qkc-sh )os h5)i df2z2 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 fi2b5 buzyuo6k1g-ck373i f(vdlu ,zpn eld directed into the page. The wire experiences an induced charge separatio276ubgp5o u z( yl,v3bdkn3c fizu -k1n as shown. Which way is the wire moving?

  00.20: A wire moves with a velocity v through a magnetic field andqvl 05;vmo p-k experiences an induced charge separation qov-l k50pvm;as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a uddraok ):en .,kh 9;jbar moving to the right on two conducting rails. To make an induced current i in the direction indicated, in what direction would )jne urh, d.:ka9;odkthe magnetic field be in the area contained within the conducting rails?

  00.10: When a wire moving through a magnetic field has a voltage inducemqbyx22( uj9ed between the wire’s ends, that vuj22e(x yb9q moltage 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 longrvabu a: i)k02 copper rod has constant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all k bau2:ia0v)rmutually perpendicular. What is the potential difference induced across the rod’s length?

  04.42: A solenoid is orienterx99c.qznn0 y d end-on so that its opening is perpendicular 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 solenoic.0yrn 9z9qxnd, 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 * n1bx :v8)07j h*9dtaiyukfy6rbh tv the diagram (which are assumed to be close to each other), the resistance of the left-fk*yv8v0xa9h :)*6 7ibb dnyr tjh1uthand 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 magne -;blo o2kyf(pt is held very 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 through the resistor shown and what is the direction of the force on t-bok fp(;l2oyhe magnet because of the induced current?

  09.37: For the figure shown, the variable re 4ovce:)qwz5 ssistance 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 wha 5s):zec4qvow t direction is the conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar magnet is hcbn.6 r.9dtzpt7 ( f4kht vzu)eld 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 divp7 ..kztr(zb fch9t 4utd 6)nrection 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 as:vjouzq2 ,z4du *c5sloj u8;j in the j:,z o;dujlz2* vsjo 8u5u4cqfigure. 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 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 theb w7q9,1 nuecc 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 in xgn*-ugp))uhp; toh7nercircuit $R_{inner}$ 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 perpen+kbp x.q +6/4p,tte ,dzjywcydicular to a spatially uniform magnetic field pointing into the plane of the page as shown. The magnetic f ,wk4tp+, yb6 x/.pdzcjt+yeqield 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 clos42 fr2bl; 6)lko(cmvk eg/x ele to a wire with conventional current directed up the page. A scientist then moves the loops away from r;l m(vf6 bcx) k/k4eel22 olgthe current as shown. What is the orientation of the conventional current in each loop while this occurs?

  17.35: A metal bar is movin8s9kbktse y 5*g to 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 9 8*kbtyesks5indicates 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 shoj* 9wku)h,y,kj) ugbj*lgq*hwn. The magnetic field of the solenohjqb)* ,gh) k yu* uj9jwg,k*lid, 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 zg73)m6ss ms mthe 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 li mm)sg7 m6ssz3ght 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?