How is the direction of magnetic field at a point determinedusing the field lines

The direction of the magnetic field at a point is determined using the field lines in the following way:

1. First, you need to identify the magnetic field lines. These are imaginary lines that represent the magnetic field. They are drawn such that the tangent at any point on the line gives the direction of the magnetic field at that point.

2. The direction of the magnetic field is taken to be the direction in which a north pole of the compass needle moves inside the field. So, if you place a compass at a point in the magnetic field, the direction that the north end of the compass needle points is the direction of the magnetic field.

3. Therefore, by convention, the field lines outside the magnet, always direct from the North pole to the South pole. Inside the magnet, the direction of field lines is from its South pole to its North pole.

4. Thus, the magnetic field lines are always closed curves.

5. If the magnetic field lines are closer together, the magnetic field is stronger. If the magnetic field lines are further apart, the magnetic field is weaker.

6. Remember, no two field-lines are found to cross each other. If they did, it would mean that at the point of intersection, the compass needle would point towards two directions, which is not possible.