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Electricity & Magnetism
ΦB=BAcos⁡θ\Phi_B = BA\cos\theta

Magnetic flux through a surface.

Variables

Φ_B
Magnetic flux
Flux through surface
Wb
B
Magnetic field
Field strength
T
A
Area
Loop area
m²
θ
Angle
Between B and normal
°

Derivation

Φ = ∫B·dA. For uniform field: Φ = BA cos θ.

Your notes

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Common questions

What is the Magnetic Flux formula?

Magnetic Flux is written Φ_B = BAcosθ. Magnetic flux through a surface. It belongs to Electricity & Magnetism, under Electromagnetic Induction.

What are the units in Φ_B = BAcosθ?

In SI units, Φ_B is magnetic flux, measured in kg·m²/(A·s²); B is magnetic field, measured in kg/(A·s²); A is area, measured in m²; θ is angle, measured in rad.

How is the Magnetic Flux formula derived?

Φ = ∫B·dA. For uniform field: Φ = BA cos θ. The result is Φ_B = BAcosθ.