Question

A plastic ball has a charge of -10-10 C. How many more of fewer electrons does the ball have?

Answer 1

Charge of the plastic ball = q = - 10^-10 C.

Now, charge of one electron = e = 1.6 x 10^-19 C, in magnitude.

Hence, if the ball has lost n number of electrons, then, ne must be equal to magnitude of q.

So, ne = q

or, n = q / e = 10^-10 C / ( 1.6 x 10^-19 C ) ~ 6.25 x 10⁸.

Now, since the ball has a net negative charge in it, there must be excess of electrons, because electrons are negatively charged particles.

Hence, the ball has 6.25 x 10⁸ excess electrons in it.