Question

Two small spheres 18cm apart have equal negativity charge and repel each other with the force 6×10^-8.find the total charge on both spheres ​

Answer 1

given, seperation between spheres, r = 18cm = 18 × 10^-2 m = 0.18 m

repulsive force acting between them, F = 6 × 10^-8 N

using Coulomb's law,

F = KqQ/r²

a/c to question, charges on both spheres have equal in magnitude.

so, q = Q

now, F = kq²/r²

or, 6 × 10^-8 = 9 × 10^9 × q²/(0.18)²

or, (2/3) × 10^-17 × (0.18)² = q²

or, 0.0216 × 10^-17 = q²

or, 0.216 × 10^-18 = q²

or, 0.46 × 10^-9 = 0.46 nC = q

hence, charge on each sphere is -0.46n C [ as question mentioned, charge is negative in nature ].