Total magnetic field from two long parallel wires

In summary, two parallel wires, 10.0 cm apart and carrying equal 4.00-A currents in the same direction, were shown in the figure. Point p, located at the center of the wires, was used to find the magnetic field at point p2, which is 20cm directly above p. The equation B=\mu_{0}I/(2*pi*r) was used to determine the magnetic field for each wire, with the right-hand rule being used to determine the direction. To get the correct answer, the value of 4*pi*10^-7 * 4 / ( 2*pi *.206) was multiplied by the cosine of 14 and then multiplied by 2. The use of cosine instead
  • #1
physstudent1
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Homework Statement



Two long, straight, parallel wires, 10.0 cm apart carry equal 4.00-A currents in the same direction, as shown in the figure. ( in the figure the current carrying wires are at the end of a straight 10cm line and they are each in the direction coming out of the page).
point p is at the center of the 10cm line.
find the magnetic field at point p2 which is 20cm directly above p

Homework Equations





The Attempt at a Solution



I have no idea how to do this, for the last problem before this it wanted to know the field 25cm to the right of p, so I used the equation B=[tex]\mu_{0}[/tex]I/(2*pi*r) for each wire and used the right hand rule to determine they were both facing up so I added them. I'm confused on what to do now though.
 
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  • #2
I figured out to the the right answer you need to do 4*pi*10^-7 * 4 / ( 2*pi *.206) take this answer and multiply by the cos of 14 and multiply that by 2 but I don't get why you would do the cos of 14 and not the sin of 14 can someone explain it to me please
 
  • #3


I would approach this problem by first understanding the concept of magnetic fields and how they are created by electric currents. I would then use the relevant equations and principles, such as the Biot-Savart law, to calculate the magnetic field at point P2.

The Biot-Savart law states that the magnetic field at a point due to a current-carrying wire is directly proportional to the current, the length of the wire, and inversely proportional to the distance from the wire. In this case, we have two parallel wires with equal currents, so we can use the principle of superposition to determine the total magnetic field at point P2.

First, we can calculate the magnetic field due to one wire using the equation B = μ0I/(2πr), where μ0 is the permeability of free space, I is the current, and r is the distance from the wire. Since the wire is 10 cm long and the point P2 is 20 cm directly above point P, the distance from the wire would be √(10^2 + 20^2) = 22.36 cm.

Next, we can use the principle of superposition to add the magnetic fields from each wire. Since the wires are parallel and the currents are in the same direction, the magnetic fields will add together. Thus, the total magnetic field at point P2 would be twice the magnetic field calculated from one wire.

Therefore, the final equation would be B = 2(μ0I/(2πr)) = μ0I/πr. Plugging in the values for μ0, I, and r, we can calculate the magnetic field at point P2 to be approximately 3.61 x 10^-6 T.

In summary, as a scientist, I would use my understanding of magnetic fields and relevant equations to calculate the magnetic field at point P2 due to two parallel wires carrying equal currents. This approach ensures accuracy and reliability in the solution.
 

Related to Total magnetic field from two long parallel wires

What is the total magnetic field from two long parallel wires?

The total magnetic field from two long parallel wires can be calculated using the formula B = μ0I/2πd, where B is the magnetic field, μ0 is the permeability of free space, I is the current in the wires, and d is the distance between the wires. This formula is known as the Biot-Savart law.

Do the currents in the parallel wires affect the total magnetic field?

Yes, the currents in the parallel wires have a direct effect on the total magnetic field. The greater the currents, the stronger the magnetic field will be. In addition, if the currents are flowing in opposite directions, the magnetic fields will cancel out and result in a weaker overall field.

What is the direction of the total magnetic field from two long parallel wires?

The direction of the total magnetic field depends on the direction of the currents in the wires. If the currents are flowing in the same direction, the magnetic field will be parallel to the wires and in the same direction. If the currents are flowing in opposite directions, the magnetic field will be perpendicular to the wires.

How does the distance between the parallel wires affect the total magnetic field?

The distance between the parallel wires has an inverse relationship with the total magnetic field. As the distance increases, the magnetic field decreases and vice versa. This is because the magnetic field follows an inverse square law, meaning that the strength of the field decreases as the distance increases.

Can the total magnetic field from two long parallel wires ever be zero?

Yes, the total magnetic field can be zero if the currents in the wires are equal and flowing in opposite directions, and the wires are positioned at equal distances on either side of the point where the magnetic field is being measured. This is known as a null point, and it occurs because the magnetic fields from the two wires cancel each other out at that specific point.

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