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#insulator

2 public questions tagged with this topic.

Coulomb's Law and Force Between Point Charges

What explains why the electric field due to a charged object can penetrate an insulator but not a conductor?

**Inverse-square law** for charges states F ∝ 1/r² while increasing with charge product. Using k = 9×10⁹ N·m²/C², force at distance r follows F = k q₁q₂/r², forming basis for pairwise force calculation. Insulators lack free charges to redistribute and cancel an external field, allowing it to penetrate. Conductors, with mobile charges, redistribute them to create an opposing field, shielding the interior from penetration. Substituting values gives Charge mobility, which matches expected magnitude for this electrostatic configuration, confirming Coulomb's and Gauss's principles and charge quantization consistency.

Ref: NCERT > Physics Book > Electric Charges and Fields > Coulomb's Law and Force Between Point Charges

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Electric Field and Electric Field Lines

Why does the electric field inside a charged insulator depend on the distribution of charges within it?

**Field intensity** at distance r follows inverse-square law E = (1/4π ε₀)·q/r². At midpoint between two charges, fields superpose vectorially; if charges opposite, fields add in same direction, enhancing magnitude to E = E₁ + E₂. Fixed charges in an insulator create a field based on their spatial arrangement. Gauss’s law shows the field at a point depends on the enclosed charge, which varies with position due to the immovable nature of the charges. Substituting values gives Charge distribution, which matches expected magnitude for this electrostatic configuration, confirming Coulomb's and Gauss's principles and charge quantization consistency.

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

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