Coulomb's Law Calculator

Enter any three inputs and click on Calculate button


\(F = k \cdot \frac{ q₁ \cdot q₂ }{ r ^2 } \)

q₁ : C
q₂ : C
r : m
k : N.m2/C2
F : N





How to use this Coulomb's Law Calculator 🤔

  1. There are input fields for Charge \((q₁)\), Charge \((q₂)\), Distance \((r)\), Coulomb's constant \((k)\), and Electrostatic Force \((F)\). Enter any three inputs and click on Calculate button.
  2. The calculator uses the \(F = k \cdot \frac{ q₁ \cdot q₂ }{ r ^2 } \) formula, substitues given values, and calcuates the missing value(s).
  3. A missing value is calcuated and displayed in the input field. Also, the caculation is displayed under the input section.

What is Coulomb's Law?

Coulomb's Law describes the force of attraction or repulsion between two charged particles. It states that the force between two charges is directly proportional to the product of their charges and inversely proportional to the square of the distance between them. This law helps us understand the behavior of electric charges.

Calculating the Force Between Two Charges

The force (F) between two charges can be calculated using the formula:

\( F = k \cdot \frac{ q_1 \cdot q_2 }{ r^2 } \).

In this formula, the parameters are defined as follows:


Input and Output Combinations of the Coulomb's Law Calculator

Here are the input combinations available for the calculator, along with the formulas it uses to calculate the corresponding outputs.

Calculator InputsSet #1
  • q₁ Charge
  • q₂ Charge
  • r Distance

For these given inputs,

Outputs, Formulas

We calculate the following outputs:

  • Electrostatic Force\(F = \)\( k \cdot \frac{ q₁ \cdot q₂ }{ r ^2 } \)
2 Examples
Calculator InputsSet #2
  • q₁ Charge
  • q₂ Charge
  • F Electrostatic Force

For these given inputs,

Outputs, Formulas

We calculate the following outputs:

  • Distance\(r = \)\( \sqrt{ k \cdot \frac{ q₁ \cdot q₂ }{ F } }\)
1 Example


Examples

1

What is the Electrostastic Force between two objects charged at 0.01 C and 0.0001 C respectively, and are separated by a distance of 10 m ?

Answer

Given:

  • magnitude of charge on first object, q₁ = 0.01 C
  • magnitude of charge on second object, q₂ = 0.0001 C
  • distance between the two objects, r = 10 m

Calculating electrostatic force (F)...

\( F = \) \( k \cdot \frac{ q₁ \cdot q₂ }{ r ^2 } \)

\( F = \) \( 8.98755 \times 10^9 \times \frac{0.01\times0.0001}{10^2 } \)

\( F = \) 89.8755 N

2

What is the Electrostastic Force between two objects charged at 0.000001 C and 1e-7 C respectively, and are separated by a distance of 2 m ?

Answer

Given:

  • magnitude of charge on first object, q₁ = 0.000001 C
  • magnitude of charge on second object, q₂ = 1e-7 C
  • distance between the two objects, r = 2 m

Calculating electrostatic force (F)...

\( F = \) \( k \cdot \frac{ q₁ \cdot q₂ }{ r ^2 } \)

\( F = \) \( 8.98755 \times 10^9 \times \frac{0.000001\times1e-7}{2^2 } \)

\( F = \) 0.0002 N

3

Calculate the distance between two objects charged at 2 C and 5 C respectively, and the electrostatic force between these two objects is 89875 N ?

Answer

Given:

  • magnitude of charge on first object, q₁ = 2 C
  • magnitude of charge on second object, q₂ = 5 C
  • Electrostatic Force between the two charges, F = 89875 N

Calculating distance (r)...

\( r = \) \( \sqrt{ k \cdot \frac{ q₁ \cdot q₂ }{ F } }\)

\( r = \) \( \sqrt{ 8.98755 \times 10^9 \times \frac{2\times5}{89875} } \)

\( r = \) 1000.0028 m


Input and Output Combinations of the Coulomb's Law Calculator

Here are the input combinations available for the calculator, along with the formulas it uses to calculate the corresponding outputs.

Calculator InputsSet #1
  • q₁ Charge
  • q₂ Charge
  • r Distance

For these given inputs,

Outputs, Formulas

We calculate the following outputs:

  • Electrostatic Force\(F = \)\( k \cdot \frac{ q₁ \cdot q₂ }{ r ^2 } \)
2 Examples
Calculator InputsSet #2
  • q₁ Charge
  • q₂ Charge
  • F Electrostatic Force

For these given inputs,

Outputs, Formulas

We calculate the following outputs:

  • Distance\(r = \)\( \sqrt{ k \cdot \frac{ q₁ \cdot q₂ }{ F } }\)
1 Example


Examples

1

What is the Electrostastic Force between two objects charged at 0.01 C and 0.0001 C respectively, and are separated by a distance of 10 m ?

Answer

Given:

  • magnitude of charge on first object, q₁ = 0.01 C
  • magnitude of charge on second object, q₂ = 0.0001 C
  • distance between the two objects, r = 10 m

Calculating electrostatic force (F)...

\( F = \) \( k \cdot \frac{ q₁ \cdot q₂ }{ r ^2 } \)

\( F = \) \( 8.98755 \times 10^9 \times \frac{0.01\times0.0001}{10^2 } \)

\( F = \) 89.8755 N

2

What is the Electrostastic Force between two objects charged at 0.000001 C and 1e-7 C respectively, and are separated by a distance of 2 m ?

Answer

Given:

  • magnitude of charge on first object, q₁ = 0.000001 C
  • magnitude of charge on second object, q₂ = 1e-7 C
  • distance between the two objects, r = 2 m

Calculating electrostatic force (F)...

\( F = \) \( k \cdot \frac{ q₁ \cdot q₂ }{ r ^2 } \)

\( F = \) \( 8.98755 \times 10^9 \times \frac{0.000001\times1e-7}{2^2 } \)

\( F = \) 0.0002 N

3

Calculate the distance between two objects charged at 2 C and 5 C respectively, and the electrostatic force between these two objects is 89875 N ?

Answer

Given:

  • magnitude of charge on first object, q₁ = 2 C
  • magnitude of charge on second object, q₂ = 5 C
  • Electrostatic Force between the two charges, F = 89875 N

Calculating distance (r)...

\( r = \) \( \sqrt{ k \cdot \frac{ q₁ \cdot q₂ }{ F } }\)

\( r = \) \( \sqrt{ 8.98755 \times 10^9 \times \frac{2\times5}{89875} } \)

\( r = \) 1000.0028 m