What is the nature of the magnetic field produced by a straight current-carrying conductor? Explain with the help of an experiment.

(N/A) The magnetic field produced around a straight current-carrying conductor is in the form of concentric circles with the center lying on the straight conductor.
Experiment:
$1$. Take a copper wire $AB$ and pass it through a hole in a cardboard.
$2$. Connect the ends of the wire to a battery and a key in a series circuit.
$3$. Sprinkle some iron filings uniformly on the cardboard.
$4$. Switch on the key to allow current to flow and tap the cardboard gently.
$5$. You will observe that the iron filings arrange themselves in the form of concentric circles around the wire.
$6$. If you reverse the direction of the current by changing the battery polarity,the iron filings will still form concentric circles,but the direction of the magnetic field lines will be reversed.
Conclusion: The magnetic field lines around a straight current-carrying conductor are concentric circles centered on the conductor. The direction of the magnetic field depends on the direction of the electric current.