A circular loop of radius 10 cm carrying current of 1.0 A lies in x-y plane…

A circular loop of radius 10 cm carrying current of 1.0 A lies in x-y plane. A long straight wire lies in the same plane parallel to x-axis at a distance of 20 cm as shown in figure.

Find the direction and value of current that has to be maintained in the wire so that the net magnetic field at 0 is zero.

Ans. The direction of the current in the wire must be opposite to that of the current in the loop to cancel out the magnetic field at point O. Therefore, the current in the wire should flow in the opposite direction to the current in the loop. Thus, the current in the wire should be �wire=−1.37 AIwire​=−1.37A.