Two identical charges exert a force of + 0.034 N when they are 16 cm apart. What is the magnitude of each charge?

q=3.09 x 10^-7 C

Explanation:

According to Coulomb's Law

F=k q1 q2 / r^2

Since q1 = q2 (Because charges are equal)

therefore

F=k q. q / r^2

or

F=k q^2 / r^2

Now

0.034 = 9 x 10^9 x q^2 / (0.16) ^2

or

q^2 = 0.034 x 0.0256 / 9 x 10^ 9

q^2 = 9.6 x 10^-14

Taking square root

q=3.09 x 10^-7 C