Answer:
[tex]q_2 = - 1.66\times 10^{-13} c[/tex]
Explanation:
Given data:
if two charge are opposite in charge then force will be attractive between then or vice versa
if one charge is positive then other charge will be negative
from coulomb's law
[tex]f = \frac{1\times q_1\times q_2}{4\pi \epsilon_o \times r^2}[/tex]
[tex]\frac{1}{4\pi \epsilon_o} = 9\times 10^{9}[/tex]
[tex]3.1 N = 9\times 10^{9} \frac{91.4\times q_2}{0.23^2}[/tex]
[tex]q_2 = \frac{3.1\times 0.21^2}{9\times 10^{9}\times 91.4}[/tex]
[tex]q_2 = - 1.66\times 10^{-13} c[/tex]