Calculate the value of two equal charges if they repel one another with a force of 0.1 N when situated 50 cm apart in a vacuum. (Take 1/(4πε₀) = 9 ×…
Source: JAMB · 2024
Calculate the value of two equal charges if they repel one another with a force of 0.1 N when situated 50 cm apart in a vacuum. (Take 1/(4πε₀) = 9 × 10⁹ Nm²C⁻²)
Explanation
Use Coulomb’s law with equal charges: F = kq² ÷ r². Here r = 50 cm = 0.5 m.
q² = Fr² ÷ k = (0.1 × 0.25) ÷ (9 × 10⁹) = 2.78 × 10⁻¹².
q = √(2.78 × 10⁻¹²) ≈ 1.67 × 10⁻⁶ C ≈ 1.7 μC.
The pC options are a million times too small.
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