The magnetic flux (Phi) is:

The correct answer is Option (3) → Scalar quantity and its SI unit is \( \mathrm{Tm^2} \).

The magnetic flux through a surface is the dot product of the magnetic field and the area vector.

    \( \displaystyle \Phi = \vec{B}\cdot\vec{A} = BA\cos\theta \)

A dot product of two vectors is a scalar. Its unit is the unit of \( B \) times the unit of area:

    \( \displaystyle [\Phi] = \mathrm{T} \times \mathrm{m^{2}} = \mathrm{T\,m^{2}} = \mathrm{Wb} \)

Option (1) Scalar quantity and its SI unit is \( \mathrm{Wb/m^2} \). — Incorrect. Flux is a scalar, but \( \mathrm{Wb/m^2} \) (tesla) is the unit of the magnetic field \( B \), not of flux.

Option (2) Vector quantity and its SI unit is \( \mathrm{Tm^2} \). — Incorrect. The unit is right, but flux is a scalar, not a vector.

Option (3) Scalar quantity and its SI unit is \( \mathrm{Tm^2} \). — Correct. Flux is a scalar and its SI unit is \( \mathrm{T\,m^{2}} \), which is the weber.

Option (4) Vector quantity and its SI unit is \( \mathrm{Wb/m^2} \). — Incorrect. Both parts are wrong: flux is a scalar, and \( \mathrm{Wb/m^2} \) is the unit of \( B \).

NCERT (2026-27):
Magnetic Flux – “… The SI unit of magnetic flux is weber (Wb) or tesla meter squared (T m²). Magnetic flux is a scalar quantity.”