Q. A polythene piece, rubbed with wool, is found to have negative charge of $4 \times 10^{- 7}$C. the number of electrons transferred from wool to polythene is
A) $1.5 \times 10^{12}$
B) $2.5 \times 10^{12}$
C) $2.5 \times 10^{13}$
D) $3.5 \times 10^{13}$
Explanation
(b) $n = \frac{q}{e} = \frac{4 \times 10^{- 7}}{1.6 \times 10^{- 19}} = 2.5 \times 10^{\begin{array}{r}
12 \\
\
\end{array}}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.