The force of attraction between 2 charged spheres can be explained by Coulomb's law,
It states the force of attraction is directly proportional to the magnitudes of the charges and inversely proportional to the square of the distance between the charges.
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where F - force of attraction/repulsion
q₁ and q₂ - charges of the 2 spheres
k - Coulomb's law constant
r - distance between the spheres
In the question given, the charges of the spheres remain constant in both instances, only distance changes. Therefore (kq₁q₂) = c which is a constant
then F = c / r²
first instance
6 x 10⁻⁹ N = c/ (20 cm)² ---1)
F = c/(10 cm)² --- 2)
2) / 1)
F = 6 x 10⁻⁹ x 4
F = 2.4 x 10⁻⁸ N
It states the force of attraction is directly proportional to the magnitudes of the charges and inversely proportional to the square of the distance between the charges.
/
where F - force of attraction/repulsion
q₁ and q₂ - charges of the 2 spheres
k - Coulomb's law constant
r - distance between the spheres
In the question given, the charges of the spheres remain constant in both instances, only distance changes. Therefore (kq₁q₂) = c which is a constant
then F = c / r²
first instance
6 x 10⁻⁹ N = c/ (20 cm)² ---1)
F = c/(10 cm)² --- 2)
2) / 1)
F = 6 x 10⁻⁹ x 4
F = 2.4 x 10⁻⁸ N