Q.What are magnetic field lines? Mention any two properties of them.

Magnetic field lines are drawn precisely so that the tangent at any point along a line gives the direction of B at that point.

A magnetic field line is defined as a continuous curve such that the tangent drawn at any point on it gives the direction of the resultant (net) magnetic field B at that …

Magnetic field lines always form closed loops: outside a bar magnet they go from N to S, and INSIDE the magnet they continue from S back to N to close the loop.

Unlike electric field lines (which start on positive charges and end on negative charges, because isolated electric charges exist), magnetic field lines have no starting or ending point - they form continuous closed loops, because isolated magnetic monopoles do not exist (Gauss's law for magnetism: the net magnetic flux through any closed surface is always zero). Outside a bar magnet, the field lines emerge from the N-pole and curve around …

The direction of the magnetic field at any point on a field-line map is given by the tangent to the field line at that point.

Magnetic field lines are drawn such that at every point along the line, the direction of the line (i.e., the tangent to the curve at that point) represents the direction of the net magnetic field B at that point, and the density of the lines (how closely packed they are) represents the magnitude/strength of the field. This is exactly analogous to how electric field lines repre …

The statement is True: unlike electric field lines, magnetic field lines never have a start or end point — they always close on themselves.

Electric field lines begin on positive charges and end on negative charges (since isolated + and – charges exist). Magnetic field lines, however, form continuous closed loops — outside a bar magnet they go from the North pole to the South pole, and inside the magnet they continue from the South pole back to the North pole, forming an …

Two magnetic field lines can never cross, because the field at any point has one unique direction — the tangent to the field line there.

A magnetic field line is defined such that the tangent to it at any point gives the direction of $\vec{B}$ at that point. If two field lines were to intersect, then at the point of intersection there would have to be two different tangent directions — meaning the magnetic field would have two different directions at the same point simultaneously, which is physically impossible (the net field at a point is a single, unique vector obtained by vector-adding all contributions).

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Magnetic field lines form closed loops; outside a bar magnet they go from N to S, and to close the loop they must run from S to N inside the magnet.

Unlike electric field lines (which start on positive charges and end on negative charges, since isolated charges exist), magnetic field lines have no beginning or end - they always form closed continuous loops, because isolated magnetic monopoles do not exist. Outside a bar magnet, the field lines emerge from the North pole and curve around to enter the South pole. For these to form closed loops, inside the body of the magnet the field lines must continue from the South pole to the North pole, completing the circuit. So th …

All three of (1), (2), (3) are true properties of magnetic field lines; only (4) is false, since two field lines can never cross.

Magnetic field lines: form continuous closed loops (a, true), the tangent at any point gives the net field direction there (b, true), and their density (lines per unit area) represents field strength (c, true). Two field lines can never intersect — at an intersection point the field would have two directions at o …

Magnetic field lines form closed loops: outside a bar magnet they go from N to S, and inside the magnet they continue from S back to N to close the loop.

Outside the magnet, field lines emerge from the N-pole and enter the S-pole. Since field lines must form continuous closed loops (no beginning or end, unlike electric field lines which start/end on c …