At what distance should two 1C charges be kept in air for them to experience an electric force of repulsion of 10N ?

Using Coulomb's Law:

F = k × |q₁ × q₂| / r²

• F: Force between the charges (10 N)
• k: Coulomb's constant = 8.9875 × 10⁹ N·m²/C²
• q₁ and q₂: Charges (both 1 C)
• r: Distance between the charges (to be calculated)

Calculation:

Rearrange the formula to solve for r:

r = √(k × |q₁ × q₂| / F)

Substituting the known values:

r = √((8.9875 × 10⁹ N·m²/C²) × (1 C × 1 C) / 10 N)

r = √((8.9875 × 10⁹) / 10)

r = √(8.9875 × 10⁸)

r ≈ 30,000 meters (30 km)

Final Answer

The charges should be placed approximately 30 kilometers apart to experience a repulsive force of 10 newtons.