Coulomb's law

Author - Jasmin Patel

6:13 PM

According to Coulomb's law:

The electrostatic force of attraction or repulsion between two point charges is directly proportional to the product of charges.
The electrostatic force of attraction or repulsion between two point charges is inversely proportional to the square of distance between them.

Coulomb's law calculates the electric force F between two electric charges q₁ and q₂ with distance of r:

$F=k\frac{q_1\cdot q_2}{r^2}$

F is the force on q₁ and q₂ measured in newtons [N].

k is Coulomb's constant k = 8.988×10⁹ N·m²/C²

q₁ is the first charge in coulombs [C].

q₂ is the second charge in coulombs [C].

r is the distance between the 2 charges in meters [m].

When charges q1 and q2 is increased, the force F is increased.

When distance r is increased, the force F is decreased.

Find the force between 2 electric charges of 2×10^-5C and 3×10^-5C with distance of 40cm between them.

q₁= 2×10^-5C

q₂= 3×10^-5C

r = 40cm = 0.4m

F = k×q₁×q₂/ r² = 8.988×10⁹N·m²/C² × 2×10^-5C × 3×10^-5C / (0.4m)² = 37.705N