Consider a closed curve enclosing an area A (as shown in the figure). Let there be a uniform magnetic field **B** in that region. The magnetic flux through the area **A** is given by

Φ = **B**.**A = B A CosΘ**

where **Θ** is the angle which the vector** B** makes with the normal to the surface. If **B** is perpendicular to **A**, then the flux through the closed area **A** is zero.

**SI unit** of magnetic flux is * weber (Wb)*.

## Notes :

- Area vector is ⊥ to the surface.
- For open surface choose one direction as the area vector direction and stick to it for the whole problem.
- For closed surfaces outward normal is taken as area vector direction
- Flux is basically count of number of lines crossing a surface
- [because magnetic field lines exists in closed loop.]

## 1 thought on “Magnetic Flux”