How do you trace the magnetic field lines around a bar magnet using compass needle ? Explain. Write the properties of magnetic field Lines.

Explanation

i] Take a small compass and a bar magnet. Place a magnet on a sheet of white paper fixed on a drawing board. Mark the boundary of the magnet.
ii] Place the compass near the north pole of the magnet mark the position of two ends of the needle.
iii] Now move the needle to a new position such that the south pole occupies the position previously occupied by its north pole.
iv] In this way proceed step by step till we reach the south pole of the magnet. Join the points marked on the paper by a smooth curve. This represents field line .
v] Repeating above procedure we can draw as many lines as possible .
Properties of magnetic field lines :
Field lines emerge from north pole and merge at the south pole .
At the poles field lines are crowded .
No two field lines are found to cross each other .