An infinite line charge has a linear charge density of \( 4 \times 10^{-6} \, \text{C/m} \). What is the electric field
**Charge density formulation** allows integration over extended bodies, but highly symmetric cases yield simple expressions. Infinite line gives E ∝ λ/r, unlike point charge 1/r², reflecting different geometry of source. E = (2 k λ/r) , k = 9 × 10⁹ N·m²/C² . E = (2 × 9 × 10⁹ × 4 × 10⁻⁶/0.08) = 9 × 10⁵ N/C . Substituting values gives 9.0 × 10⁵ N/C, 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 > Continuous Charge Distribution