Practice question

Stokes’ law: F = 6πηav. η = 2.7×10−3Pa s, a = 0.025m, v = 0.08m/s. F = 6×3.14×2.7×10−3×0.025×0.08 = 1.017×10−4N. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 1.0 × 10⁻⁴ N. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.