Two point charges +2μC and -3μC are separated by 30 cm. The force on each (k = 9 × 10⁹):
A0.6 N
B0.06 N
C60 N
D6 N
Answer & Solution
Correct answer: A. 0.6 N
F = kq₁q₂/r² = (9 × 10⁹)(2 × 10⁻⁶)(3 × 10⁻⁶)/(0.3)² = (9 × 10⁹)(6 × 10⁻¹²)/0.09 = 54 × 10⁻³/0.09 = 0.6 N. Attractive (opposite signs).
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