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# What is the total charge on 75.0 kg of electrons ?

$(a)\;1.33\times10^{13}\;C\qquad(b)\;-1.33\times10^{13}\;C\qquad(c)\;-1.2\times10^{-17}\;C\qquad(d)\;3.93\times10^{13}\;C$

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• The SI unit of quantity of electric charge is the coulomb, which is equivalent to about $6.242 \times 10^{18}$ e (e is the charge of a proton). Hence, the charge of an electron is approximately $?1.602 \times 10^{?19}$ C.
Answer : $\;-1.33\times10^{13}\;C$
Explanation : Number of electrons in 75 kg = $\;\large\frac{75}{9.11\times10^{-31}}$
$=8.23\times10^{31}$
Mass of one $\;e^{-}=9.11\times10^{-3}\; kg$
Charge on these electrons = $\;-8.23\times10^{31}\times1.6\times10^{-19}$
$=-1.31\times10^{13}\;C$
edited Jan 29, 2014 by yamini.v