Finding magnitude of external field from two magnetic fields

In summary, the conversation discusses determining the magnitude of an external field needed to cancel out two magnetic fields in two parallel wires with opposite currents. The individual magnetic field for one wire is found to be 0.000210526 and this value is used for the total force of repulsion between the two wires.
  • #1
rosstheboss23
37
0

Homework Statement


I was wondering how would you determine the magnitude an external field needed to cancel two magnetic fields in two wires? In this instance the currents of the two wires are in opposite directions...so I know there is a repulsion force.
The currents in both wires are equal to 20 amps apiece
The wires are parallel to each other and are 0.019meters apart.


Homework Equations


Going about this problem I thought this would be useful F(magnetic)= (Current)(Length)(Magnetic field)
Also I thought this would be useful B= (4piE-7)(I) divided by (2pie X r)


The Attempt at a Solution


When I tried to plug in the values for B I got 0.000210526 for the magnetic field in one wire. If I double this I get 0.000421053 for the total force of repulsion. Would this be the correct way of approaching the problem.
 
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  • #2
No, just go with the 0.00021. That's the magnetic field due to one wire, at the location of the other wire.
 
  • #3
Thank you. I really appreciate your help.
 

What is the equation for finding the magnitude of an external magnetic field from two magnetic fields?

The equation for finding the magnitude of an external magnetic field from two magnetic fields is B_ext = sqrt(B1^2 + B2^2). This is known as the Pythagorean theorem for vector addition.

How do I determine the direction of the external magnetic field from two magnetic fields?

The direction of the external magnetic field can be determined by using the right hand rule. Point your right thumb in the direction of the first magnetic field and your index finger in the direction of the second magnetic field. Your middle finger will then point in the direction of the external magnetic field.

What is the difference between an external magnetic field and a magnetic field created by a magnet or current?

An external magnetic field is a field that is created by sources outside of the system being observed, such as the Earth's magnetic field. A magnetic field created by a magnet or current is a field that is generated within the system, such as a bar magnet or a wire with current flowing through it.

Can the magnitude of an external magnetic field be negative?

No, the magnitude of an external magnetic field cannot be negative. Magnitude refers to the size or strength of a vector quantity, and it is always a positive value.

What are some real-life applications of finding the magnitude of external magnetic fields?

One common application is in the field of geophysics, where scientists use this calculation to map the Earth's magnetic field and study its variations. It is also used in industries such as navigation and mineral exploration, as well as in medical imaging techniques like MRI.

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