Answer:
2.4×10⁻⁵ C
Explanation:
From coulomb's law,
F = kqq'/r²..................... Equation 1
Where F = force on each charge, q = magnitude of the first charge, q' = magnitude of the second charge, r = distance between both charges, k = coulomb's constant.
From the question,
q' = 2q
Therefore,
F = 2kq²/r².............. Equation 2
make q the subject of the equation
q = √(Fr²/2k).................... Equation 3
Given: F = 65 N, r = 40 cm = 0.4 m.
Constant: k = 9×10⁹ Nm²/C²
Substitute this values into equation 3
q = √[(65×0.4²)/(2×9×10⁹)]
q = √(5.78×10⁻¹⁰)
q = 2.4×10⁻⁵ C
