Question

An infinitely long thin metal strip of width w=12cm carries a current of I=10A that is uniformly distributed across its cross section. What is the magnetic field at point P a distance a=3cm above the center of the strip?

I have tried using the integration method but cannot get the correct answer :(

Answer 1

Use symettry as you integrate across. Starting from one side, all you want to add is the horizontal component (the vertical component will be oposite direction when you get to the other side).

So integrate the cosine/sine Theta part of the angle only (theta equals an angle from the strip to the point, the cos/sin will depend on how you label the angle).

Answer 2

I don't understand.