Answer:
3.74 mm
Explanation:
From coulomb's law,
F = kqq'/r²............... Equation 1
Where F = force, q and q' = the two charges, r = distance between the two charges, k = proportionality constant.
making r the subject of the equation
r = √(kqq'/F)...................... Equation 2
Given: q = q' = 90 nC = 90×10⁻⁹ C, F = 5.20 N, k = 9.0×10⁹ Nm²/C²
Substitute into equation 2,
r = √(90×10⁻⁹ )².√(9.0×10⁹/5.2)
r = 90×10⁻⁹.√(17.31×10⁸)
r = (90×10⁻⁹)(4.16×10⁴)
r = 374.4×10⁻⁵ m
r = 3.74 mm
Hence the distance between the charge = 3.74 mm