Electric flux is zero when the electric field is parallel to the surface area, meaning the angle between the electric field vector and the normal vector to the surface is 90 degrees.
Here's a more detailed explanation:
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Electric Flux Defined: Electric flux is a measure of the number of electric field lines passing through a given surface. It's proportional to the electric field's strength and the area of the surface.
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The Formula: The electric flux (ΦE) through a surface is given by:
ΦE = E A cos(θ)
Where:
- E is the magnitude of the electric field.
- A is the area of the surface.
- θ is the angle between the electric field vector and the normal vector to the surface. The normal vector is perpendicular to the surface.
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Zero Flux Condition: For electric flux to be zero, one or more of the terms in the equation must be zero. The electric field (E) and the area (A) are generally non-zero. Therefore, cos(θ) must be zero.
cos(θ) = 0 when θ = 90 degrees.
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Visualizing Zero Flux: Imagine an electric field flowing parallel to a flat surface. None of the electric field lines actually pass through the surface; they just skim along its surface. This corresponds to zero flux.
Therefore, the electric flux is zero when the angle between the electric field vector and the normal vector to the surface is 90 degrees.
