94.20: A magnet is dropped through a vertical coppe 8xr9+xqm0kmga a 33y zelpb0)r pipe slightly larger than the magnet. Relative to the speed ip g r0m38m)x+eb 3 0lzxqa9aykt would fall in air, the magnet in the pipe falls:

  01.30: Lenz's law concerningc0: *9mn v/8hvoj thui the direction of an induced current in a conductor by a magnetic o:h/v8m cj 09*hunitvfield could be a restatement of

  11.25: The product (3 Teslas) × (2 meters) × (4 meters/seco1gej++g /z k7s kfuz1+*j mhpynd) is equivalent to which one ofpu khj+*zj+fz1e my1/+ gskg 7 the following?

  04.34: A square loop is p l bt; ce3a4:e2pie,wmlaced 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 ana bl2e3emc:t iwe,4; pgle 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 4n jgefdyp7 3.)yi9 hnfield directed into the page. The wire experiences an induced charge separation as shown. Which wagepy4jdyih9)n f .37 ny is the wire moving?

  00.20: A wire moves with a velocity v through a svg :rz4z* d ivb s2c0 h)fk)z8gn)ot,magnetic field and experiences an induc2gni)zd0zk *grb zh84)fs) t:o,s vvced charge separation as shown. What is the direction of the magnetic field?

  05.33: The figure below shows a bar moving to the right o 03o4vbm*l kvnn two conducting rails. To make an induced current i in the direction indicated,mv04v3l bk o*n 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 has a voltage -bxq elt16jg 3:l(v xninduced between the wire’s ends, thab (x3ejx q 1tnv6g-:llt 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 trave5d8m2eq vnj0z ling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is thvj 8 52nmqezd0e potential difference induced across the rod’s length?

  04.42: A solenoid is orientedo 0 qa;m az11;qdpzki/br j50u 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 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 dirq u1imjbd 0;;1a0zk5z a q/opmmest.

  07.34 For the solenoids shzw5iwf 3,5+x6hkvq eg own in the diagram (which are assumed to be close to each other), the resistance of the lef hzg, v3kq6 x+e55fiwwt-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 jqpf : b.be3*e*zhhy*rxz -4tto 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 hfzy*h3:q- pjbt er* *bx 4ez.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 circuijwm/n(6y2tdg8eg8 uubdlm+3 t 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(mtw uln/y8+jb26mgu d g3de 8-hand circuit and in what direction is the conventional current through the resistor in the right-hand circuit?

  10.39: A strong bar npmp2gp5-k m23w r r4mmagnet is held 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 direction -np g2p w5m3p2kr mmr4of 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 5df(s kan 2 j3tu:swh)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 of the left-hand loop) a (uasdn:52sh)3 fjkwtnd 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 the outer circuil)pp-f k9n4m ca -(hnzt $R_{inner}$ 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 pnpn/r+ae4pq q-ki:-9t grt1 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 sits in a plane perpendicularitrkj*4)mv m wc )i/q:t be o71oh0)mn to a spatially uniform magnetic field pointing into the plane of the page as shown. The magn7mn1ok)i:etcm 0bvo/ h r))t*4iqm jw etic 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 conventional cu w m,pd(5ttff/xec3h -rrent directed up thepmtxc5e(f3tw hfd ,/- page. A scientist then moves the 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 acrod 1c)atm p,*qgss a set of frictionless conducting rails as seen in the figure. Throughout the region between the cd1*pm a,)gqtrails, 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 resistor at the instant shown?

  08.50:. An infinitely long sollah1yj j zvu6f k ,,af-+;q tlc+q(uj4enoid passes through the circuit as shown. The magnetic field of the solenoid, directed infq,kj(qj+af1,ja u 4l;cvl+t -yuh 6 zto 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 8r4agu 6z o 4sfk9zor8is 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 rz98u r4z fk a8s4oog6R 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?