Prove when the current are opposite, two parallel wires repel each other?

Question

thank you

Answer 1

Let there be two wires X and Y carrying current in opposite direction. The magnetic field at the position of Y due to current in X Is vertically downwards (using right-hand thumb rule). Applying Fleming's left-hand rule to find the direction of force on Y, we get that the force is directed away from X. Same will be the case of X. So, the two power wires will move away from each other.