Practice question

**Electric field** defined as E = F/q₀, force per unit positive test charge, unit N/C or V/m, direction along force on positive test charge. For point charge, E = k q/r² radially outward for q>0. Field lines start on positive and end on negative, density indicates strength. E = (sigma/2 ε₀) . E = (8.85 × 10⁻¹¹/2 × 8.854 × 10⁻¹²) = 5 N/C . Substituting values gives 5.0 N/C, which matches expected magnitude for this electrostatic configuration, confirming Coulomb's and Gauss's principles and charge quantization consistency.