College Physics (7th Edition)

(a) Charge on the fur is positive. As rubber rod acquire negative charge, it means it has gain electrons. those electrons get transferred to rubber from fur so fur is positively charged. (b)$2.73\times10^{-20}kg$ mass is transferred from fur to rubber rod.
(a) Charge on the fur is positive. As rubber rod acquire negative charge, it means it has gain electrons. those electrons get transferred to rubber from fur so fur is positively charged. (b) the total electron lost by fur is gained by the rubber rod . so if the charges of those electron is $-4.8\times10^{-9}C$ for rubber rod, for fur total charge lost would be $+4.8\times10^{-9}C$. Charge of electron $e= -1.6\times10^{-19}C$. so $1.6\times10^{-19}C$ is equal to $1$ electron $1C$ is equal to $\frac{1}{1.6\times10^{-19}}$electron $4.8\times10^{-9}C$ is equal to $\frac{4.8\times10^{-9}}{1.6\times10^{-19}}$electron = $3\times10^{10}$ electrons mass of electron $m_{e}=9.1\times10^{-31}kg$ so total mass= No.of electrons X mass of one electron total mass= $3\times10^{10}\times9.1\times10^{-31}kg=2.73\times10^{-20}kg$ so $2.73\times10^{-20}kg$ mass is transferred from fur to rubber rod. (c) Fur lost mass in terms of electron.These electrons are gained by the rubber rod so rubber rod gained $2.73\times10^{-20}kg$ of mass.