Question Number 52846 by peter frank last updated on 13/Jan/19
Answered by peter frank last updated on 14/Jan/19
Commented by peter frank last updated on 14/Jan/19
$$\left.{a}\right)\:{r}=\sqrt{\frac{\mathrm{9}\eta{v}_{\mathrm{1}} }{\mathrm{2}\left(\rho−\sigma\right){g}}} \\ $$$$\left.{b}\right)\:{drop}\:{to}\:{be}\:{stationary} \\ $$$${qE}=\frac{\mathrm{4}}{\mathrm{3}}\pi{r}^{\mathrm{3}} \left(\rho−\sigma\right){g} \\ $$$${E}=\frac{{v}}{{d}} \\ $$$${excess}\:{no}\:{of}\:{electron} \\ $$$${n}=\frac{{q}}{{e}} \\ $$$$..... \\ $$