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Two long, parallel wires carry currents of different magnitudes. If the amount of current in one of the wires is doubled, what happens to the magnitude of the force that each wire exerts on the Other?


A) It is increased by a factor of 8 .
B) It is increased by a factor of 4.4 .
C) It is increased by a factor of 2.2 .
D) It is increased by a factor of 3 .
E) It is increased by a factor of 2\sqrt { 2 }

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A proton is projected with a velocity of 7.0 km/s into a magnetic field of 0.60 T perpendicular to the motion of the proton. What is the magnitude of the magnetic force that acts on the proton? (e = 1.60×1019C1.60 \times 10 ^ { - 19 } \mathrm { C } )


A) 13×1016 N13 \times 10 ^ { - 16 } \mathrm {~N}
B) 6.7×1016 N6.7 \times 10 ^ { - 16 } \mathrm {~N}
C) 0 N0 \mathrm {~N}
D) 3.4×1016 N3.4 \times 10 ^ { - 16 } \mathrm {~N}
E) 4.2×1016 N4.2 \times 10 ^ { - 16 } \mathrm {~N}

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A wire in the shape of an "M" lies in the plane of the paper. It carries a current of 2.0 A2.0 \mathrm {~A} , flowing from AA to EE , as shown in the figure. It is placed in a uniform magnetic field of 0.85 T0.85 \mathrm {~T} in the same plane, directed as shown on the right side of the figure. The figure indicates the dimensions of the wire. Note that ABA B is parallel to DED E and to the baseline from which the magnetic field direction is measured. What are the magnitude and direction of the force acting on section DE of this wire?  A wire in the shape of an  M  lies in the plane of the paper. It carries a current of  2.0 \mathrm {~A} , flowing from  A  to  E , as shown in the figure. It is placed in a uniform magnetic field of  0.85 \mathrm {~T}  in the same plane, directed as shown on the right side of the figure. The figure indicates the dimensions of the wire. Note that  A B  is parallel to  D E  and to the baseline from which the magnetic field direction is measured. What are the magnitude and direction of the force acting on section DE of this wire?   A)   0.30 \mathrm {~N}  perpendicular out of the page B)   0.30 \mathrm {~N}  perpendicular into the page C)   0.20 \mathrm {~N}  perpendicular out of the page D)   0.12 \mathrm {~N}  perpendicular into the page E)   0.12 \mathrm {~N}  perpendicular out of the page


A) 0.30 N0.30 \mathrm {~N} perpendicular out of the page
B) 0.30 N0.30 \mathrm {~N} perpendicular into the page
C) 0.20 N0.20 \mathrm {~N} perpendicular out of the page
D) 0.12 N0.12 \mathrm {~N} perpendicular into the page
E) 0.12 N0.12 \mathrm {~N} perpendicular out of the page

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Three long parallel wires each carry 2.0-A currents in the same direction. The wires are oriented vertically, and they pass through three of the corners of a horizontal square of side 4.0 cm4.0 \mathrm {~cm} . What is the magnitude of the magnetic field at the fourth (unoccupied) corner of the square due to these wires? (μ0=4π×107 Tm/A) \left( \mu _ { 0 } = 4 \pi \times 10 ^ { - 7 } \mathrm {~T} \cdot \mathrm { m } / \mathrm { A } \right)


A) 12μT12 \mu \mathrm { T }
B) 21μT21 \mu \mathrm { T }
C) 2.1μT2.1 \mu T
D) 1.2μT1.2 \mu \mathrm { T }
E) 0 T0 \mathrm {~T}

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A charged particle that is moving in a static uniform magnetic field


A) may experience a magnetic force, but its speed will not change.
B) may experience a magnetic force which will cause its speed to change.
C) will always experience a magnetic force, regardless of its direction of motion.
D) may experience a magnetic force, but its direction of motion will not change.
E) None of the above statements are true.

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Two long parallel wires placed side-by-side on a horizontal table carry identical current straight toward you. From your point of view, the magnetic field at a point exactly between the two wires


A) is zero.
B) points away from you.
C) points toward you.
D) points downward.
E) points upward.

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A flat circular loop of wire is in a uniform magnetic field of 0.30 T0.30 \mathrm {~T} . The diameter of the loop is 1.01.0 m\mathrm { m } , and a 2.0-A current flows in it. What is the magnitude of the magnetic torque on the loop when the plane of the loop is parallel to the magnetic field?


A) 0.00 Nm0.00 \mathrm {~N} \cdot \mathrm { m }
B) 0.47 Nm0.47 \mathrm {~N} \cdot \mathrm { m }
C) 0.52 Nm0.52 \mathrm {~N} \cdot \mathrm { m }
D) 0.41 Nm0.41 \mathrm {~N} \cdot \mathrm { m }

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A wire lying in the plane of this page carries a current directly toward the top of the page. What is the direction of the magnetic force this current produces on an electron that is moving Perpendicular to the page and outward from it on the left side of the wire?


A) toward the bottom of the page
B) toward the top of the page
C) perpendicular to the page and towards you
D) perpendicular to the page and away from you
E) The force is zero.

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An electron moves with a speed of 3.0×104 m/s3.0 \times 104 \mathrm {~m} / \mathrm { s } perpendicular to a uniform magnetic field of 0.400.40 T. What is the magnitude of the magnetic force on the electron? (e=1.60×1019C) \left( e = 1.60 \times 10 ^ { - 19 } \mathrm { C } \right)


A) 4.8×1014 N4.8 \times 10 ^ { - 14 } \mathrm {~N}
B) 0 N0 \mathrm {~N}
C) 2.2×1024 N2.2 \times 10 - 24 \mathrm {~N}
D) 5×1020 N5 \times 10 - 20 \mathrm {~N}
E) 1.9×1015 N1.9 \times 10 - 15 \mathrm {~N}

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A thin copper rod 1.0 m long has a mass of 0.050 kg and is in a magnetic field of 0.10 T. What minimum current in the rod is needed in order for the magnetic force to balance the weight of the Rod?


A) 9.8 A
B) 4.9 A
C) 2.5 A
D) 1.2 A

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Two long parallel wires separated by 7.5 cm7.5 \mathrm {~cm} each carry 3.3 A3.3 \mathrm {~A} in opposite directions. (μ0=\left( \mu _ { 0 } = \right. 4π×107 Tm/A4 \pi \times 10 ^ { - 7 } \mathrm {~T} \cdot \mathrm { m } / \mathrm { A } ) (a) What magnetic force per length acts on each of the wires? Is it attractive or repulsive? (b) Find the magnitude of the magnetic field midway between the two wires.

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(a) blured image, repu...

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The magnetic field at a distance of 2 cm2 \mathrm {~cm} from a long straight current-carrying wire is 4μT4 \mu \mathrm { T } . What is the magnetic field at a distance of 1 cm1 \mathrm {~cm} from this wire?


A) 6μT6 \mu \mathrm { T }
B) 8μT8 \mu \mathrm { T }
C) 2μT2 \mu T
D) 10μT10 \mu \mathrm { T }
E) 4μT4 \mu T

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If a calculated quantity has units of NAm\frac { \mathrm { N } } { \mathrm { A } \cdot \mathrm { m } } , that quantity could be


A) a magnetic field.
B) μ0\mu _ { 0 } .
C) a magnetic torque.
D) an electric field.
E) an electric potential.

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A geophysicist measures the magnetic force on a proton that is moving vertically downward at a point 1.996 km/s1.996 \mathrm {~km} / \mathrm { s } at the earth's equator. At that Iocation, the earth's magnetic magnetic field is horizontal and has a strength of 0.40×104 T0.40 \times 10 ^ { - 4 } \mathrm {~T} . What are the magnitude and direction of the force she will measure? (e=1.60×1019C)\left( e = 1.60 \times 10 ^ { - 19 } \mathrm { C } \right)

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After landing on an unexplored Klingon planet, Spock tests for the direction of the magnetic field by firing a beam of electrons in various directions and by recording the following observations: Electrons moving upward feel a magnetic force in the northwest direction. Electrons moving horizontally toward the north are pushed downward. Electrons moving horizontally toward the southeast are pushed upward. Mr) Spock therefore concludes that the magnetic field at this landing site is in which direction?


A) toward the southeast
B) toward the west
C) toward the east
D) toward the northeast
E) toward the southwest

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Three particles travel through a region of space where the magnetic field is out of the page, as shown in the figure. What are the signs of the charges of these three particles? Three particles travel through a region of space where the magnetic field is out of the page, as shown in the figure. What are the signs of the charges of these three particles?   A)  1 is positive, 2 is negative, and 3 is neutral. B)  1 is negative, 2 is neutral, and 3 is positive. C)  1 is neutral, 2 is positive, and 3 is negative. D)  1 is neutral, 2 is negative, and 3 is positive. E)  1 is positive, 2 is neutral, and 3 is negative.


A) 1 is positive, 2 is negative, and 3 is neutral.
B) 1 is negative, 2 is neutral, and 3 is positive.
C) 1 is neutral, 2 is positive, and 3 is negative.
D) 1 is neutral, 2 is negative, and 3 is positive.
E) 1 is positive, 2 is neutral, and 3 is negative.

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An electron moving along the +x-axis enters a magnetic field. If the electron experiences a magnetic deflection in the -y direction, then the magnetic field must have a component


A) along the -y-axis
B) along the +y-axis
C) along the -x-axis
D) along the -z-axis
E) along the +z-axis

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An electron traveling toward the magnetic north with speed 400 km/s400 \mathrm {~km} / \mathrm { s } enters a region where the earth's magnetic field has the magnitude 5.0×105 T5.0 \times 10 ^ { - 5 } \mathrm {~T} and is directed downward at 4545 ^ { \circ } below horizontal. What magnitude magnetic force acts on the electron? (e=1.60×1019C)\left( e = 1.60 \times 10 ^ { - 19 } \mathrm { C } \right)

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A straight 1.0m1.0 - \mathrm { m } long wire is carrying a current. The wire is placed perpendicular to a magnetic field of strength 0.20 T0.20 \mathrm {~T} . If the wire experiences a force of 0.60 N0.60 \mathrm {~N} , what is the current in the wire?


A) 4.0 A4.0 \mathrm {~A}
B) 3.0 A3.0 \mathrm {~A}
C) 5.0 A5.0 \mathrm {~A}
D) 2.0 A2.0 \mathrm {~A}
E) 1.0 A1.0 \mathrm {~A}

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A proton, moving west, enters a magnetic field. Because of this magnetic field the proton curves upward. We may conclude that the magnetic field must have a component


A) towards the west.
B) towards the north.
C) towards the south.
D) towards the east.
E) downward.

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