Question

What are magnetic field lines ? How is the direction of magnetic field at a point in a magnetic field determined using field lines ?

Answer 1

The imaginary lines representing magnetic field around a magnet is known as magnetic field lines.

The direction of the magnetic field line at a point can be determined using Maxwell's right hand thumb rule.

Answer 2

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$\large{\underline{\underline{\red{\bf{\purple{\leadsto } More\:To\:Know:-}}}}}$

✤ The SI unit of magnetic field intensity is Tesla ( T ) or Weber / m² .

✤ The CGS unit of magnetic field intensity is Gauss ( G ) . [ 1T = 10⁴ G ]

✤ Magnetic field lines come out from north pole to south pole outside the magnet and from South to North pole inside the magnet.

✤ Magnetic field is a vector quantity because its complete specification needs both direction as well as magnitude.

✤The magnetic field perpendicular to a plane in outward direction is denoted by ' • ' . On the other hand the magnetic field perpendicular to the plane in inward direction is denoted by ' × ' .

$\large{\underline{\underline{\red{\bf{\purple{\leadsto } Properties\:Of\: Magnetic\:Field\:Lines:-}}}}}$

✤These are always closed loops.

✤The magnetic field lines never intersect each other. if we imagine that they will intersect each other then at that two point two tangents can be drawn to determine the direction and hence that point will have two directions which is not possible.

✤ Direction of magnetic field line at a point can be e determined by by drawing tangent to that point.

✤The density of lions is proportional to the strength of magnetic field.

✤In the region of strong magnetic field the magnetic field lines converge and in the region of weaker magnetic field magnetic field lines diverge.