Answer
q=$3.2\times 10^{-19}C$
Work Step by Step
Electrostatic force is given as:
$F=\frac{Kq_1q_2}{r^2}$
The ions are identical, so $q_1=q_2=q$
Hence, $F=\frac{Kq^2}{r^2}$
This simplifies to:
$q^2=\frac{F.r^2}{K}$
$q=\sqrt{\frac{F}{K}}r$
Plugging in the known values, we obtain:
$q=\sqrt\frac{3.7\times10^{-9}}{9\times10^9}.(5.0\times 10^{-10})$
q=$3.2\times 10^{-19}C$
