Question

Which of the following correctly describes the magnetic field near a long straight wire?

• A. The field consists of straight lines perpendicular to the wire.
• B. The field consists of straight lines parallel to the wire.
• C. The field consists of radial lines originating from the wire.
• D. The field consists of concentric circles centred on the wire.

Answer 1

The correct option is D The field consists of concentric circles centred on the wire.

Using right hand thumb rule one can easily see the direction of magnetic field line caused by a long straight wire carrying a current I.It will be co-centric around the current carrying conductor.