Current must flow in the loop in clockwise direction to produce zero magnetic field at its centre.
Step-by-step explanation:
Magnetic fields have both directions and magnitudes. Hall probes can determine the field’s magnitude. The field around the long straight wires is formed by circle loops.
The right hand rule results from this study and applies to every current segment. It states that point your thumb towards the current direction and your fingers will curl towards the magnetic field loops created due to this.
In the shown figure, due to current-carrying wire, magnetic field is in upward direction. Hence, to make that into zero the ring’s current must flow such that magnetic field will be in downward direction.
To find direction with the help of Right hand thumb rule, should curl our finger in current direction so that thumb will show us the magnetic field’s direction.
In order for magnetic field in downward direction, the ring’s current flow should be in clockwise. Ultimately, the magnetic field by wire and ring get cancel out each other.