Which of the following principles may be used to determine the direction of the magnetic field around a straight current-carrying wire?

According to Maxwell's Corkscrew rule, if the screw is rotated in the direction of the current, the direction of the magnetic field is determined by the direction of rotation of the screw.

According to the right-hand thumb rule, if the current-carrying conductor is held in the right hand with the thumb pointing in the direction of the current, the fingers will encircle the wire in the direction of the magnetic field.

Columb's law explains the force of attraction or repulsion acting along a straight line between two electric charges. 

Hence, the direction of the created magnetic field around a straight current-carrying wire may be found by.

1. The corkscrew rule of Maxwell

2. Thumb rule on the right