Question

If a body contains $n_1$ electrons and $n_2$ protons, the total amount of charge on the body is

• A. $(n_1-n_2)e$
• B. $(n_2-n_1)e$
• C. $(n_1+n_2)e$
• D. $⟮\frac{n_1+n_2}{2}⟯e$

Answer 1

The correct option is B $(n_2-n_1)e$

Both protons and electrons contain charge equals 1 but opposite magnitude. Add the number of electrons and protons (n1 + n2) to count the number of charges. To calculate the total amount of charge on the body we must consider the path of the charge whether it is negative or positive. Because electrons and protons are opposite charges, the total charge on the body is the algebraic sum of the positive and negative charges on the body, that is (n2 – n1).