# Homework Help: Magnetic Field at center of a Square loop

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1. Mar 20, 2016

### Elvis 123456789

1. The problem statement, all variables and given/known data
A square wire loop 12.0 cm on each side carries a clockwise current of 15.0 A

Find the magnitude of the magnetic field at its center due to the four 1.30 −mm wire segments at the midpoint of each side.

2. Relevant equations
B = (μ0*I)/(4π)*(2a)/(x√(x^2+a^2))

3. The attempt at a solution
I used the above equation for magnetic field at the center of the square loop due to one wire and then multiplied it by 4 since the contribution due to each wire segment is the same by symmetry.

B = 4*(4π*10^-7*15)/(4π)*(2*0.06)/(0.06*√(0.06^2+0.06^2))

B = 1.41*10^-4 T

This answer is wrong and I don't know why

2. Mar 20, 2016

### drvrm

are you permitted to add them like scalars -as they are magnetic field vectors and their addition-rules are different.

3. Mar 20, 2016

### Elvis 123456789

As far as i know, the contributions from each wire are equal and in the same direction, so i can add them.

4. Mar 20, 2016

### drvrm

You might have heared about Biot-Savart Law for calculating the B field due to current element -or see a reference to see the direction of the field.
Ref.http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magcur.html

5. Mar 20, 2016

### Elvis 123456789

Yes, I used the law from scratch to end up with the result that I have. My problem is that I don't know where I am going wrong.

6. Mar 21, 2016

### drvrm

what is in your opinion the correct answer should be and how it differs from your calculation.?

7. Mar 21, 2016

### Elvis 123456789

I already figured out how to do the problem. No offense, but none of your replies helped in any way, at all. This isn't me trying to come at you in any way. I just found your replies to be either not relevant to the question, or just really vague like your last reply. Thanks for trying to help anyways though.