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Electricity & Magnetism
F=kq1q2r2F = k\frac{q_1 q_2}{r^2}

Electric force between two point charges.

Variables

F
Electric force
Force between charges
N
k
Coulomb constant
8.99×10⁹
N·m²/C²
q₁
Charge 1
First charge
C
q₂
Charge 2
Second charge
C
r
Distance
Between charges
m

Derivation

Fundamental law. k = 1/(4πε₀).

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Common questions

What is the Coulomb's Law formula?

Coulomb's Law is written F = kq₁ q₂/r². Electric force between two point charges. It belongs to Electricity & Magnetism, under Electrostatics.

What are the units in F = kq₁ q₂/r²?

In SI units, F is electric force, measured in kg·m/s²; k is coulomb constant, measured in kg·m³/(A²·s⁴); q₁ is charge 1, measured in A·s; q₂ is charge 2, measured in A·s; r is distance, measured in m.

How is the Coulomb's Law formula derived?

Fundamental law. k = 1/(4πε₀). The result is F = kq₁ q₂/r².