A plastic rod gains a charge of \( -1.92 \times 10^{-7} \, \text{C} \) when rubbed. How many electrons were transferred
**Charge conservation and quantization** govern rubbing processes where electrons transfer without creation. Total charge before and after remains equal, and any measured charge corresponds to n = q/e electrons, allowing counting of carriers from coulomb value. Negative charge means electrons gained. q = n e , e = -1.6 × 10⁻¹⁹ C . n = (q/|e|) = (1.92 × 10⁻⁷/1.6 × 10⁻¹⁹) = 1.2 × 10¹² . Substituting values gives 1.2 × 10¹², 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 Charge, Quantization and Conservation