# Magnetic flux through a coil. Field generated by a straight conductor.

1. Dec 20, 2011

### Biktor

Hi! I'm stuck on a problem concerning the magnetic field produced by a long straight conductor:

A triangular piece of conductor (N=1) rests in the vicinity of a long straight conductor with a current I=50A. What is the magnetic flux through the triangle if a=1cm? (See attached file).

My approach was to try to integrate to find how the field from the conductor varies with distance to be able to find the field's strength in that triangle and then multiply it with the area to get the flux, but I'm getting it all wrong.

Is there any general approach to this kind of problem?

The correct answer is 7.7*10^-8 Wb.

Thanks!

#### Attached Files:

• ###### Current.png
File size:
458 bytes
Views:
213
2. Dec 20, 2011

### technician

I think you are correct in the need to integrate to find the flux through the triangle.
The main piece of information that I can give is that the magnetic flux density (B) at a distance 'a' from a long straight wire is given by:

B = μI/2πa

I am rusty on integration !!!! but if you can apply this to the area of the triangle it should help
I calculate that B at a distance a=1cm from the wire is 1 x 10^-3T
and B at a distance of 2a = 0.5 x 10^-3T

I have forgotten how to integrate over the area of the triangle.... sorry