A spray tube (5cm2) has 25 holes of diameter 1.0mm. If the flow speed is 2.4m/min, what is the ejection speed?
A1v1 = A2v2, v1 = 2.4m/min = 0.04m/s, A1 = 5×10−4m2. Hole area: Ah = π(0.5×10−3)2, total A2 = 25×π×2.5×10−7≈1.963×10−5m2. v2 = 5×10−4×0.041.963×10−5≈1.02m/s. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 1.02 m/s. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.
Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.