Question

A constant current flows in a horizontal wire in the plane of the paper from east to west as shown in Figure. The direction of magnetic field at a point will be North to South when the point is _____ .

• A. directly above the wire
• B. directly below the wire
• C. at a point located in the plane of the paper, on the north side of the wire
• D. at a point located in the plane of the paper, on the south side of the wire

Answer 1

The correct option is B

directly below the wire

The direction of the magnetic field can be determined by right-hand rule - "When the thumb points in direction of the current, the direction of curling of fingers will give the direction of magnetic field."

Therefore only at a point directly below the wire, the magnetic field will be exactly from north to south.