203- How many electrons must be removed from the surface of a plastic ball by friction so that its weight change can be measured with a sensitivity of $0.1$ milligrams, and approximately how many coulombs of electric charge does this number of electrons carry? (The charge of an electron is approximately $1.6 \times 10^{-19}$ C and $g \approx 9 \times 10^{-28}$ g.) \begin{align*} &(1) 1.78\times10^{5}, 3/011\times10^{22} &(2) 1.66\times10^{4}, 1/11\times10^{22} &(3) 1.648\times10^{5}, 3/011\times10^{22} &(4) 1.78\times10^{4}, 1/11\times10^{22} \end{align*}
\textbf{203-} How many electrons must be removed from the surface of a plastic ball by friction so that its weight change can be measured with a sensitivity of $0.1$ milligrams, and approximately how many coulombs of electric charge does this number of electrons carry? (The charge of an electron is approximately $1.6 \times 10^{-19}$ C and $g \approx 9 \times 10^{-28}$ g.)
\begin{align*}
&(1)\quad 1.78\times10^{5},\quad 3/011\times10^{22} \qquad &(2)\quad 1.66\times10^{4},\quad 1/11\times10^{22}\\
&(3)\quad 1.648\times10^{5},\quad 3/011\times10^{22} \qquad &(4)\quad 1.78\times10^{4},\quad 1/11\times10^{22}
\end{align*}