Question

What are magnetic field lines write the properties of magnetic field lines

Answer 1

The lines along which the iron filings align themselves in a magnetic field represent magnetic field lines. 
The properties are;
1. The magnetic field lines are closed curves.
2. no two field lines can ever intersect each other.
3.the field lines emerge from the north pole and merge at the south pole.

Answer 2

Answer:

Magnetic Field Lines:

• Magnetic field lines are paths along which a hyoothetical free north pole would tend to move.
• A pictorial representation of magnetic field lines is very useful in visualizing the strength and direction of the magnetic field.
• The direction of magnetic field lines is defined to be the direction in which the north end of a compass needle points.

Properties of Magnetic Field lines:

• Field line arise from North pole and end into South pole of the magnet.
• Field lines are closed curves.
• Field lines are closer in stronger magnetic fields.
• Field lines never intersect each other as for two lines to intersect, there must be two north directions at a point which is not possible.
• Direction of field lines inside a magnet is from South to North.
• The relative strength of magnetic field is shown by degree of closerness of field lines.
• H.C. Oersted was the first person to state that electrical current has magnetic field.