With the help of a labelled circuit diagram, illustrate the pattern of field lines of the magnetic field around a current-carrying straight long conducting wire. How is the right hand thumb rule useful to find direction of magnetic field associated with a current-carrying conductor?

Explanation

Take a thick straight conductor XY and pass it through the centre of a thick carboard. Connect the ends of the conductor to the terminals of a battery through a Rheostat Rh, a key K and and ammeter (A) so that current flows from Y to X , when we sprinkle some iron fillings on the carbdoard, these average themselves in concentric cicles around O when carbdoard is gently tapped.
Thus, the pattern of concentric circles indicateing the field line of a magnetic field is observed. These concentric cicles represent the magnetic field around a current carrying straigth wire become larger and larger as we move away from it.
We use right thumb rule to find the direction of magnetic field. if follows as imagine the straight conductor in your right hand such that the thumb points in the direction of current
Then, the direction of asking of fingres of the right hand gives the direction of magnetic field lines.