A constant current flowing in a horizontal wire in the plane of the paper from East to West is shown in Figure. The direction of magnetic field at a point will be from North to South: W E N S W E
(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.
Using right-hand thumb rule, magnetic field lines appear in Clockwise direction ie.,
- from South to North above the wire
- from North to South below the wire
So, the correct answer is (b)