Two point charges `q_(A) =3 mu c` and `q_(B)=-3 mu` c are located 20 cm apart in a vacuum
(a) what is the electric field at the midpoint O of the line AB joining the two charges
(b) if a negative test charge of magnitude `1.5 xx 10^(-9)` c is placed at this point what is the force experienced by the test charge

Explanation

(a) `5.4 xx10^(6) NC^(-1)` along OB
(b) `8.1 xx10^(-3) N` along OA