Question

Two equal and like charge when placed 5cm apart experience a repulsive force of 0.144 newton .the magnitude of the charge in microcoloumb will be

Answer 1

Let the charge on each object is q
Given, separation between them , r = 5cm = 0.05 m
force act between them , F = 0.144N [ repulsive force ]

Now, according to Coulombs law,
F = Kq²/r²
0.144 = 9 × 10⁹ × q²/(0.05)²
0.016 × (0.05)² × 10⁻⁹ = q²
Taking square root both sides,
0.4 × 0.05 × 10⁻⁵ = q
q = 0.02 × 10⁻⁵ C = 0.2 × 10⁻⁶ C

Hence, magnitude of each charge = 0.2μC