Two point sized charged bodies repel each other with a force of 20 N when 30 cm apart in air. If their combined charge is `30 muC`, find the charge present on each body.

Explanation

(i) Let `q_(1),q_(2)` be the charge of each particle.
`q_(1) + q_(2) = 30 muC`,
According to Coulomb's law
`F = (1)/(4piin_(0)) xx (q_(1)q_(2))/(r^(2))`
Determine the value of `q_(1),q_(2)` from the given information.
Use the relation `(q_(1) - q_(2))^(2) = (q_(1)+q_(2))^(2) - 4q_(1)q_(2)`
And find `q_(1) - q_(2)`
Solve `q_(1) + q_(2)` and `q_(1) q_(2)`to obtain the value of `q_(1)` and `q_(2)`
(ii) `q_(1) = 10 xx 10^(-6)C, q_(2) = 20 xx 10^(-6)C`
`q_(1) = 20 xx 10^(-6)C, q_(2) = 10 xx 10^(-6)C`