Question

An object carries a charge q=-4.8*10 -6 C. calculate the number of electrons corresponding to this charge

Answer 1

The charge on a single electron is $q_e=1.6\times 10^{−19}\;C$ . All other charges in the universe consist of an interger multiple of this charge ($q=nq_e$ ). This is known as charge quantisation.

A negatively charged object has an excess of electrons on its surface.

$n = \frac{q}{q_e}$

$n = \frac{-4.8 \times 10^{-6}}{1.6\times 10^{-19}}$

$n = 3\times 10^{13}$

Answer: 3×10¹³