Magnetic flux through any closed surface around magnetic pole is always zero. The correct reason for this fact, is
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Magnets are always dipoles
Gauss's law for magnetism states that the net magnetic flux through any closed surface is zero. The reason is that isolated magnetic poles (monopoles) do not exist: the simplest magnetic element is a dipole. Every field line that enters a closed surface also leaves it, so the flux in and the flux out cancel.
Option (1) Magnets always exist in pairs — Incorrect. It is the two poles of a magnet that always occur together, not magnets themselves; a single magnet can exist on its own.
Option (2) Magnets are always dipoles — Correct. Because every magnet is a dipole, no closed surface can enclose a net pole, so the net flux is zero.
Option (3) Magnets can exist as monopoles — Incorrect. Monopoles have never been found; if they existed, the flux through a surface around one would not be zero.
Option (4) No magnet exerts force on another magnet — Incorrect. Magnets do exert forces on each other; this has nothing to do with the flux.
NCERT (2026-27):
Magnetism and Gauss’s Law – “… The difference between the Gauss’s law of magnetism and that for electrostatics is a reflection of the fact that isolated magnetic poles (also called monopoles) are not known to exist. There are no sources or sinks of B; the simplest magnetic element is a dipole or a current loop. All magnetic phenomena can be explained in terms of an arrangement of dipoles and/or current loops. Thus, Gauss’s law for magnetism is:
The net magnetic flux through any closed surface is zero.”