How To Calculate Force Between Two Charges

Coulomb's Law:

\[ F = k \frac{q_1 q_2}{r^2} \]

Charge 1 (q₁):

Charge 2 (q₂):

Distance (r):

Medium:

Electrostatic Force (F):

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1. What Is Coulomb's Law?

Coulomb's Law describes the electrostatic force between two charged particles. It states that the magnitude of the electrostatic force between two point charges is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them.

2. How Does The Calculator Work?

The calculator uses Coulomb's Law:

\[ F = k \frac{q_1 q_2}{r^2} \]

Where:

\( F \) — Electrostatic force (N)
\( k \) — Coulomb's constant (8.99 × 10⁹ N·m²/C² in vacuum)
\( q_1, q_2 \) — Electric charges (C)
\( r \) — Distance between charges (m)

Explanation: The force is attractive if charges have opposite signs and repulsive if they have the same sign. The calculator considers the medium's effect through relative permittivity.

3. Importance Of Electrostatic Force Calculation

Details: Understanding electrostatic forces is fundamental in electromagnetism, electronics, atomic physics, and materials science. It helps predict interactions in charged systems and design electrical devices.

4. Using The Calculator

Tips: Enter charges in coulombs, distance in meters, and select the appropriate medium. Ensure distance is greater than zero and use appropriate units for accurate results.

5. Frequently Asked Questions (FAQ)

Q1: What is Coulomb's constant?
A: Coulomb's constant (k) is approximately 8.99 × 10⁹ N·m²/C² in vacuum and relates to the permittivity of free space as \( k = \frac{1}{4\pi\epsilon_0} \).

Q2: How does medium affect the force?
A: Different media have different relative permittivity (εᵣ), which reduces the electrostatic force compared to vacuum. Water (εᵣ≈80) significantly reduces the force.

Q3: What are typical charge values?
A: Elementary charge is 1.6 × 10⁻¹⁹ C. Practical charges range from microcoulombs (10⁻⁶ C) to millicoulombs (10⁻³ C) in many applications.

Q4: Is this valid for all distances?
A: Coulomb's Law is exact for point charges and approximately valid for spherical symmetric charge distributions when r is much larger than charge dimensions.

Q5: How does force direction work?
A: Like charges repel (positive force), opposite charges attract (negative force). The calculator shows magnitude; direction depends on charge signs.