Question

A polythene piece rubbed with wool is found to have negative charge of $3.2\times {10}^{-7}C$. Estimate the number of electrons transferred from wool to polythene.

• A. $2\times {10}^{12}$
• B. $3\times {10}^{12}$
• C. $4\times {10}^{12}$
• D. $5\times {10}^{12}$

Answer 1

The correct option is A $2\times {10}^{12}$

$Q=ne$
where $e=1.6\times {10}^{-19}C$
Thus,
$3.2\times {10}^{-7}C=ne$
$\frac{3.2\times {10}^{-7}C}{1.6\times {10}^{-19}C}=n$
$n=2\times {10}^{12}$