Question

Two point charge Q1 and Q2 are 3m apart, and their combined charge is 20micro coulumb.

(a) if one repels the other with a force of 0.075N, what are the two charges?

(b) if one attract the other with a force of 0.525N, what are the magnitude of the charges?

Answer 1

$q_1q_2=\frac{Fr^2}k,$

a)

$q_1q_2=75,$

$q_1+q_2=20,$

$q_1=15~\mu C,$ $q_2=5~\mu C,$

b)

$q_1q_2=25,$

$q_1+q_2=20,$

$q_1=18.7~\mu C,$ $q_2=1.3~\mu C.$