{{tag>charges ballon chapter1_2}}
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#@TaskTitle_HTML@##@Lvl_HTML@#~~#@ee1_taskctr#~~ Charges on a Ballon                   #@TaskText_HTML@#   

A balloon has a charge of $Q=7~{\rm nC}$ on its surface. \\ 
How many additional electrons are on the balloon?

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\begin{align*}
Q         &=   7~{\rm nC} = 7\cdot 10^{-9}~{\rm C} \\
n_{\rm e} &= {{7*10^{-9}~{\rm C}}\over{1.6022*10^{-19}~{\rm C/electron}}} 
           = 43.7*10^{9}~{\rm electrons}
\end{align*}
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#@ResultBegin_HTML~1~@#
\begin{align*}
43.7*10^{9}~{\rm electrons} 
\end{align*}
#@ResultEnd_HTML@#


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