# Homework Help: Biot Savart's Law

1. Jan 26, 2012

### Baydith

1. The problem statement, all variables and given/known data

Calculate magnetic field intensity in point P using Biot-Savart's law. How should the supplying wires be arranged so that they would not influence field in P point? a=0.2m,i=10A

2. Relevant equations

Biot Savart's law

3. The attempt at a solution

In the attachment.

The tutor graded my work for only 3 (that is C), whereas I don't quite understand why. Could anyone tell me what was wrong with my solution?

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2. Jan 27, 2012

### vela

Staff Emeritus
Isn't segment 2 supposed to be a circular arc? Do you have a scan of the original diagram?

3. Jan 27, 2012

### Baydith

The scan is in the attachment, it is linear, therefore from the equation, this segment does not contribute to the magnetic field. However, I'm wondering how to place all the wires that they would not contribute to the magnetic field...

4. Jan 27, 2012

### vela

Staff Emeritus
From your work, you seem to have more information than was shown on the problem statement. Where did that all come from?

I didn't check your work closely, but I didn't see any obvious errors. Have you asked your tutor for clarification?

As far as the arrangement of the supply wires goes, think about the fact you have one segment that doesn't contribute to the magnetic field at P. Why doesn't it? How can you apply that concept to the supply wires?