State ‘Cork screw rule’ and ‘Right hand thumb rule’.
Cork screw rule
Direction of magnetic lines of force around a straight current carrying conductor can be determined by these rules.
‘Cork screw rule’ says that, the direction of magnetic lines of force around a straight current carrying conductor is the same as that in which the cork screw must be rotated to cause to an advance in the direction of the current in conductor.
Right hand thumb rule
Grasp the conductor with right hand in such a way that the extended thumb must be in the direction of current in the conductor. Then the folded fingers or encircling fingers must be in the direction of magnetic lines of force around the conductor.