Gauss’s Law: Electric Field & Flux

Use the sliders to change the point charge Q and the Gaussian surface radius r. Yellow arrows = the E-field direction.

Gauss’s Law: Φ_E = ∮ E · dA = Q_enc/ε₀

Legend & Quick Guide

Point charge at center (blue color means −Q)

Gaussian surface (wireframe sphere)

Electric-field arrows on the Gaussian surface

Conducting shell (transparent)

Tip: Move r into the conductor region (between 19 and 20). You should observe E = 0 and Φ = 0.

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Charge Q (µC):

Gaussian radius r:

Region

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Q_enc (µC)

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E on surface (N/C)

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Flux Φ (Φ = Q_enc / ε₀)

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Only true for spherical symmetry:

Check: Φ ≈ E(4πr²) = —