Question

how many neutral points are there when two bar magnets are placed antiparallel to earth's magnetic field

Answer 1

two is the neutral points

Answer 2

As a result of two magnetic fields acting at the same place, the resultant field has a special feature. At a particular point, if the compass needle does not point in any particular direction, then there is no net magnetic field at the point. Such a point is called Neutral point or the Null point.

A neutral point is a point where the resultant magnetic field is zero.

Figure (a) and (b) shown below illustrate the null points when the magnet is placed in two different positions.





When the N pole of the magnet points South and the magnet in the magnetic meridian.

When the N pole of the magnet points North and the magnet in the magnetic meridian.

At the two points marked X in figure, the earth's magnetic field and the magnet's field are exactly equal and opposite and the resultant field is zero. These points are called the neutral points.