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#infinite sheet

2 public questions tagged with this topic.

Energy Stored in Capacitor and Energy Density

Why does the electric field due to an infinite charged sheet remain constant with distance from the sheet?

**Energy stored in capacitor** U = ½ C V² = ½ Q V = Q²/(2C) (J), C capacitance (F), V voltage (V), Q charge (C). For 4 μF charged to 250 V, U=0.5×4×10⁻⁶×62500=0.125 J. Energy resides in electric field, energy density u = ½ ε₀ E² (J/m³), E field between plates. Using Gauss’s law for an infinite charged sheet with surface charge density sigma , a Gaussian surface (e.g., a cylinder perpendicular to the sheet) shows that the electric field E is perpendicular to the sheet and constant. The flux through the cylinder's end caps is E · 2A , and the enclosed charge is

Ref: NCERT > Physics Book > Electrostatic Potential and Capacitance > Energy Stored in Capacitor and Energy Density

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Electric Field and Electric Field Lines

Why does the electric field due to an infinite charged sheet remain constant regardless of its thickness?

**Electric field concept** visualizes influence of source charge. Uniform field exerts constant force F = qE, and flux Φ = E·A = E A cosθ links field to area orientation, maximum when field normal to surface. For an infinite sheet, Gauss’s law shows the field depends only on the surface charge density ( sigma/2ε₀ ). Thickness doesn’t affect the planar symmetry or enclosed charge per unit area, keeping the field constant. Substituting values gives Surface charge density, which matches expected magnitude for this electrostatic configuration, confirming Coulomb's and Gauss's principles and charge

Ref: NCERT > Physics Book > Electric Charges and Fields > Electric Field and Electric Field Lines

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