Practice question
Question
A pipe narrows from 0.12m2 to 0.04m2. If water flows at 1.6m/s in the wider section, what is the speed in the narrower section?
Explanation
Continuity equation: A1v1 = A2v2. A1 = 0.12m2, v1 = 1.6m/s, A2 = 0.04m2. v2 = A1v1A2 = 0.12×1.60.04 = 4.8m/s. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 4.8 m/s. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.