Question

What is the value of charge on a body that carries 40 excess electrons?

Answer 1

Given
Number of electrons, n = 40
$$\begin{gathered} \mathrm{Charge}\mathrm{on}\mathrm{each}\mathrm{electron},e=1.6\times {10}^{-19}\mathrm{C} \\ \mathrm{Charge}\mathrm{due}\mathrm{to}40\mathrm{electron},q=ne \\ \mathit{\Rightarrow }q=40\times 1.6\times {10}^{-19} \\ \Rightarrow q=6.4\times {10}^{-18}\mathrm{C} \end{gathered}$$