why magnetic field lines form closed curve ??

Hello,

They  form continuous curves because field lines begin from north and end in south side. hence they form closed curves. :-)

• 20

They form continuous curves because field lines begin from north and end in south side. hence they form closed curves.

• -6

why magnetic field lines form closed curve ?

• -5

They form continuous curves because field lines begin from north and end in south side. hence they form closed curves. :-)

• 0
Imagine the air molecules around the magnet to be mini bar magnets. They each have some protons(+ve) and electrons(-ve). It is just like an electric circuit. To align themselves, they would have to be balanced by the effect of the north and south pole. They wouldn't form corners because the magnetic fields aren't strongest perpendicular to a pole. They wouldn't form in straight lines either because there is an effect from the opposite pole on the atoms in the air. Thus, they come in the form of closed curves, bending at molecular levels to form curves.
• 0
it is because magnetic field lines starts from north pole and ends at south pole.
so they form closed curves
• 15
the direction of field lines outside a magnet is from north to south while it is from south to north inside the magnet
thus forms closed curves
• -9
Thanks for this
• -5
THE DIRECTION OF FIELD LINES OUTSIDE A MAGNET IS FROM NORTH POLE TO SOUTH POLE WHILE IT IS FROM SOUTH TO NORTH POLE INSIDE THE MAGNET AND THUS FORMS A CLOSED CURVE
• 12
they are continous.

• -4

It's not correct that magnetic field lines are always closed loops. They can, for instance, extend to infinity in both directions. Or they can loop endlessly around some small volume without touching themselves- after all they are just mathematical objects with zero thickness. But what they can't do, & I assume this was your point, is end. More generally, you can look at some region in space- any shape you like & anywhere you like- and the total of the magnetic field entering & leaving it will always cancel perfectly to zero. Mathematically, this is called zero divergence.

Electric fields, on the other hand, can have plenty of divergence- anywhere you have electric charge, there are lines of force streaming out of it (or into it, depending on the sign of the charge) . The divergence is exactly proportional to the amount of charge. But not all of the electric field comes from charge- some comes from changing magnetic fields, and that part (if you are careful to split up the field in a very specific way) does have zero divergence.

So what would create magnetic fields with divergence? Obviously, magnetic charge! Now we just have to go find some. All the magnetic fields we see come from movement or spin of electric charges. Magnetic ones, called magnetic monopoles, could fit very nicely into our theories, but so far as we know, they just don't happen to exist. There are some experiments searching for them, and some models that say they should exist- a few in the universe- but so far, we more or less assume that electric fields have the monopoly (ha-ha) on divergence & charge.

• -3
The magnetic field direction is the same direction a compass needle points
• -3
because  magnetic field lines starts from north and ends at south

• -1
Magnetic field lines originate from north pole and forming a closed curve ends at south pole of the magnet Proof: Place the compass near the north pole of the bar magnet and Mark the point below it,drag the compass in the direction shown by it and keep marking lines and hence we will get a closed curve
• -2
What are you looking for?