- lines are closely packed at either poles of magnet, but are more spaced out on both sides as well as further away from the magnet
- these lines connected the opposite sides of the poles and are present within magnet
- these lines are called magnetic field lines
- magnets create these Spatial magnetic fields and the magnetic field lines are visual tools to represent magnetic fields
Characteristics of Magnetic Field Lines
- magnetic field lines never cross 1 another
- magnetic field lines are continuous + they form closed loops
- distance between magnetic field lines represents the strength of magnetic field. the closer the lines, the stronger the magnetic field.
Common to use diagram to represent magnetic field lines
By convention:
- field lines have arrows that point out from the north poles of the magnet and point to the south pole.
- since magnets are stronger at poles, these field lines are more concentrated at poles.
A uniform magnetic field has field lines.
- field lines are equally spaced + parallel to one another.
- uniform magnetic filed exerts a constant magnetic force in the region.
Opposite is true for a non uniform magnetic field.
- field lines are not equally spaced thus not parallel to each other
- at different points, magnetic force exerted would be different.
Field lines can be used to represent interaction between 2 magnets. When 2 unlike poles are placed next to each other → field lines go from north pole of one magnet to south pole of the other magnet.
- this is why unlike poles attract.
Conversely, when 2 like poles are placed next to each other → field lines move away from each other.
- this is the reason why like poles repel each other.
- point X is called neutral point because resultant magnetic field in that region is 0.
- magnetic fields are point X from each magnet are equal and opposite — they cancel each other.
If 2 bar magnets are placed side by side → magnetic field lines will interact with each other.
interaction when bar magnets are placed side by side, with unlike poles beside each other. the magnetic field lines join together and become denser at the poles
interaction when the like poles of both bar magnets are beside each other. this time, magnetic field lines bend away from each other
regions marked X are neutral regions where resultant magnetic field lines are 0
- NO MAGNETIC FIELD
CHECK
Definition
A pattern of magnetic field lines is used to represent a magnetic field. A magnetic field line is the path in which an isolated north pole would travel if it were free to move.
Sample
for most suspended / floating objects → when they are attracted/repelled to magnet → they will appear to follow magnetic field line. e.g. circular field line → object moves in circle / travel along magnetic field lines towards xx pole of magnet