Question: 28: The shape of the magnetic field lines due to an infinite long, straight current carrying conductor is :
(1) a straight line
(2) circular
(3) elliptical
(4) a plane
Answer: Option (2)
Explanation:
An infinite long, straight current carrying conductor produces a magnetic field around it.
According to the Biot–Savart law and Ampere’s circuital law, the magnetic field at any point around the conductor depends only on the distance from the wire.
The magnetic field lines form closed loops around the conductor.
These loops lie in planes perpendicular to the conductor and have the same center as the wire.
Hence, the magnetic field lines due to an infinite long,
straight current carrying conductor are circular in shape.