What are magnetic field line and how they are mapped?
Answers
The lines that we have mapped out around the magnet, called the magnetic lines of force, indicate the region in which the force of the magnet can be detected. This region is called the magnetic field.
A magnetic field is invisible, but it can be detected using a magnetic compass. A compass contains a small bar magnet on a pivot so that it can rotate. The compass needle points in the direction of the Earth’s magnetic field, or the magnetic field of a magnet.
Magnetic fields can be mapped out using small plotting compasses:
place the plotting compass near the magnet on a piece of papermark the direction the compass needle pointsmove the plotting compass to many different positions in the magnetic field, marking the needle direction each timejoin the points to show the field lines
The needle of a plotting compass points to the south pole of the magnet.
The Earth's magnetic field
The behaviour of a compass shows that the Earth has a magnetic field. Scientists believe that this field is produced by convection currents in the Earth’s core, which is made from iron and nickel. When a plotting compass is placed in the Earth’s magnetic field, the north pole of the compass will line up with the Earth’s magnetic field lines and point to magnetic south.
magnetic field lines are those under whose influence the compass needle points towards the nearer magnetic pole rather than geographic north south direction'....they have many properties....and they always move from north to south direction'....
to plot them.....
place a magnet
bring a compass near it
then draw a point on its north point on the paper and also on the south point with a pencil
then again place it's needle on the downward point
continue doing till you reach the other magnetic end
then join the lines
.....