- #1
flyingpig
- 2,579
- 1
Homework Statement
Calculate the value of magnetic flux density in air in the middle of two straight parallel wires carrying currents of 10A and 20A in the opposite directions. The distance between wires is 10cm.
The Attempt at a Solution
[tex]\oint \vec{B}\cdot d\vec{A} = \Phi[/tex]
[tex]\oint \frac{\mu_0 I}{2\pi r}\cdot d\vec{A} = \Phi[/tex]
[tex]\sum \vec{B} = \frac{\mu_0 (10)}{2\pi r} + \frac{\mu_0 (20)}{2\pi r} = \frac{\mu_0 (30)}{2\pi r} [/tex]
[tex]30\int \frac{\mu_0 }{2\pi r}\cdot d\vec{A} = \Phi[/tex]
Problem is that I don't know how to transform this into a definite integral. I don't know how long the wires are to do dA to dxdy