"Consider the four current-carrying wires described in the figure below. Each of these wires is long and straight, and carries the current I either into or out of the page, as shown."
What is the direction of the net magnetic field produced by these four wires at the center of the square?
Please see attached for diagram.
Four current carrying parallel wires are placed at the corners of a square, the magnetic field at the center of the square is calculated.