Question

Two point charges reacted with each other to produce 4.32 x 10⁻⁴ J. the magnitude of q is 27 nC with a distance from the point charge of 19 cm. Find the magnitude of the point charge

Answer 1

$$W=k\frac{q_1q_2}{r}$$

$$q_2=Wr/(kq_1)\\ =4.32*10^{-4}*0.19/(9*10^9*27*10^{-19})\\ =3.38*10^{-7}\:\rm C$$