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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