Question

A plastic ball has a charge of +5 × 10⁻¹¹ C.

(a) Does the ball have more electrons or fewer electrons than when it is electrically neutral?

(b) How many such electrons? Round your answer to the nearest integer.

Answer 1

(a) The ball have fewer electrons than when it is electrically neutral since at neutral, number of eletrons is equal to number of protons which have equal and opposite charges and hence end up with electrically neutal.

(b) The plastic ball has a charge + 5 × 10^-11 C , which is equal to amount of charges of the excess protons or the reduced electrons.

1e = 1.6 × 10 ^-19 Coulombs,

1 Coulombs = 6 × 10¹⁸ electrons

So, number of such electrons = ( 5× 10^-11)/(1.6 × 10^-19)

= 3 × 10⁸ electrons