Magnetic flux Φ due to magnetic flux density B through a flat 2D surface with area A is related to B normal to the surface A: a) B at some arbitrary angle $α(\vec{B},\hat{a})$, b) parallel to surface so $α(\vec{B},\hat{a})$=90°, c) perpendicular to the surface so $α(\vec{B},\hat{a})$=0°).
Note that Φ is always a scalar quantity, and it is only illustrated here as the red arrow to show that it is positive because B points away from the penetrated surface A.
magnetic_flux_at_angle_magnetica
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