Question

The shape of magnetic field lines around a straight current carrying wire is ___.

• A. concentric circles
• B. elliptical curves
• C. parallel lines
• D. a grid of parallel and perpendicular lines

Answer 1

The correct option is A concentric circles

Hans Christian Oersted found that a compass needle is deflected when it is brought close to a current carrying conductor. To find the nature of magnetic field lines around a conductor, the conductor is made to pass through a hole in a cardboard paper and iron filings are sprinkled on the cardboard paper.

The way the iron filings arrange themselves gives the magnetic field around that point. It is observed that the iron filings arrange themselves in concentric circles, as shown.
Hence, magnetic field lines around a straight wire carrying current forms concentric circles around the wire.