A polythene bag rubbed with a woollen jersey is found to have a negative charge of \( 3\times10^{-7}\,\mathrm{C} \). The number of electrons transferred from woollen jersey to the polythene would be:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → \( 1.875\times10^{12} \)
Charge is quantised: a body carrying n extra electrons has charge \( q = ne \), where \( e = 1.6\times10^{-19}\,\mathrm{C} \).
\( \displaystyle n = \frac{q}{e} = \frac{3\times10^{-7}\,\mathrm{C}}{1.6\times10^{-19}\,\mathrm{C}} = 1.875\times10^{12} \)
Note: This question is from NCERT (2026-27). NTA sets numerical questions from NCERT too, so do not ignore NCERT while practising numericals.
NCERT (2026-27):
Exercises – …
