Electromagnetics - Two long wires carry equal, but opposite currents

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Drevin
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Another Electromagnetics question...

Two long wires carry equal, but oppositely directed, 25 A currents. What is the magnitude of magnetic field due to these currents at point P? The wires are 0.1 m apart and point P is 0.05m in between the wires.

Would the following be the correct way to solve it?

B = (4pi * 10^-7)(25) / (2)(pi)(0.05)

(Phys. 12)
 
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Drevin said:
Another Electromagnetics question...

Two long wires carry equal, but oppositely directed, 25 A currents. What is the magnitude of magnetic field due to these currents at point P? The wires are 0.1 m apart and point P is 0.05m in between the wires.

Would the following be the correct way to solve it?

B = (4pi * 10^-7)(25) / (2)(pi)(0.05)

(Phys. 12)

1. Do you know the expression for magnetic field set up by a long straight wire (of course you do).

2. At point P can you determine the directions of the two fields (due to the two wires)?

3. Determine the fields and add them vectorially :smile:
 
HINT: The question is easier than it first seems and can be answered by inspection; no calculations are nesscary, but they could be used to obtain the same answer. Think bout what determines the magnitude of the magnetic field. Think about what determines the direction of the magnetic field.

:wink:
~H