An infinite line of charge has a linear charge density of $10^{-7} C m^{-1}$. The magnitude of the force acting on a charge $6.4 × 10^{-19} C$ kept at a distance of 8 cm from the line of charge is
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → $1.44 × 10^{-14} N$
Substituting values:
E = (9 × 10⁹ / 2π) × (10⁻⁷ / 0.08)
E = (9 × 10⁹ × 10⁻⁷) / (0.16π)
E = (9 × 10²) / (0.16π)
E ≈ 2.25 × 10⁴ N/C
Force on the charge:
F = qE
F = 6.4 × 10⁻¹⁹ × 2.25 × 10⁴
F = 1.44 × 10⁻¹⁴ N