There straight current carrying conductors A,B and C are placed parallel and adjacent to each other by an electrician as shown in the figure. Then determine the direction of resultant force acting on the wire B .

Explanation

Direction of current flowing through the wire '1' is from a to B and in wire '2' is from C to D, i.e. the current flows through the wires in the same direction. According to right hand grip rule the direction of magnetic field at the point 'P' due to the wire '1' is into the plane of the paper and that of the wire '2' is out of the plane of the paper so net magnetic field at the midpoints is zero. when the polarity of cell `'C_(1)'` changes, current flows through the wire from B to A. so, the direction of magnetic field at the point 'P' due to the two wires is out of plane of the paper. So, net magnetic field is away from the plane of the paper.