Question

what statement is false dealing with magnetic field near a straight long wire carrying constant current?

1.) magnetic field lines are a group of line perpendicular to the current?

2. there is no magnetic field near the wire

3.) magnetic field lines are a group of lines parallel to the current

4.) magentic field lines are a group of circles around the current

Answer 1

The magnetic field near a long straight wire carrying current is

B = μ_oI/2πr where I is the current and r is the distance of the point from the wire.

The direction of magnetic field around the wire is given by right hand grip rule. The field is represented by magnetic field lines which are concentric circles around a long wire.

The false statements are:

2. there is no magnetic field near the wire.

3. magnetic field lines are group of lines parallel to the current.