A straight wire conductor passes vertically through a piece of cardboard sprinkled with iron filings. A current is passed through the wire in the upward direction and the cardboard is tapped gently.
The following diagram shows the arrows that represent the direction of the magnetic field lines
Name the law you will use to find the direction of the magnetic field lines.
The correct option is D. Right hand thumb rule
Right hand thumb rule:
Take a wire which is carrying current in the right hand, then the thumb points the current direction and all other fingers surrounding the wire give the magnetic field direction due to the current.