Magnetic Field lines


by abrahamjp
Tags: field, lines, magnetic
abrahamjp
abrahamjp is offline
#1
Jan6-14, 07:18 AM
P: 6
Hello All,

I was just checking magnetic field lines as in attached figure.

I am curious to see some gaps between adjecent field lines in the figure.
Why it is not like a sheath( for example in lighting field) but as lines?

Thanx in advance

Abraham
Attached Thumbnails
iron filings sprinkled-magnetic filed.png  
Phys.Org News Partner Physics news on Phys.org
The hemihelix: Scientists discover a new shape using rubber bands (w/ video)
Mapping the road to quantum gravity
Chameleon crystals could enable active camouflage (w/ video)
Nick O
Nick O is offline
#2
Jan6-14, 07:50 AM
P: 56
There is actually a continuum of field lines, but only a finite number of discrete lines can be visualized by this method.

Others will probably give more knowledgeable answers, but I suspect that the gaps between the lines of iron fillings are caused by magnetic forces between the fillings themselves.
sophiecentaur
sophiecentaur is offline
#3
Jan6-14, 03:21 PM
Sci Advisor
PF Gold
sophiecentaur's Avatar
P: 11,395
Field lines are only a 'construct' to give an idea what the field is doing. There are alternative ways of showing the field. You can write pairs of numbers on a regular grid (magnitude and direction of the magnetic field vector) or you can draw contours of equal potential - but we are not familiar with that way. The spacing between the lines gives an indication of the strength of the field - close together means strong.
When you do the trick with iron filings, the tiny bits of iron actually affect the local H field strength and produce a local B field. This means they tend to stick together in chains. It's a stunning demonstration but you shouldn't read too much into what you see - or expect to get a 'measurement' out of the picture.
The 'holes' in the picture are where the field is too low for the filings to stick together.


Register to reply

Related Discussions
Magnetic field lines...What do they exactly mean? Classical Physics 22
Magnetic field lines Classical Physics 1
Magnetic field lines Introductory Physics Homework 2
Magnetic field lines Classical Physics 2
Magnetic Field Lines General Physics 1