# Ampere's circuital law problem

1. Nov 9, 2009

### shrabastee

1. The problem statement, all variables and given/known data
In figure. (i1 and i2 are in the same direction. And the formula for field due to straight long wire is to be used.)

2. Relevant equations

General magnetic field due to a straight long current at point P=μ0i/2πr(r=perpendicular distance between the conductor and the point P)

3. The attempt at a solution

EDIT:

These are the steps I came up with:
1)Find B1 due to conductor carrying i1
2)Find B2 due to conductor carrying i2(taking distance as (d-r))
3)Subtract the two to get net field.
4)Integrate.

But how do I eliminate the i2 from the expression??

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Last edited: Nov 9, 2009
2. Nov 9, 2009

### indr0008

the net field in each points indeed has i2 in it but when u integrate over a circle centered on the first wire, the contribution from the term that has i2 in it should result in zero

3. Nov 10, 2009

### shrabastee

Thanks! Are you sure my solution's right, though? Because this is a college problm and the solution I came up with seems a bit too simple. :P