Answer:
Right hand thumb rule : It is a rule used to find the magnetic field direction around current carrying wire .
Step-by-step explanation:
It states that : "If you grasp conductor in your right hand such that thumb points in upward direction ,then the direction in which our finger curls gives the direction of magnetic field or magnetic lines of forces" .
This rule proves that :Current can give rise to magnetism .
Around every current carrying conductor there exist a magnetic field which can be easily felt .
According to this rule : When a current flows in upward direction ,the finger curls in anticlockwise direction and when direction of current reverses ,then the direction of field also reverses .