$Assertion :$ For Reynold’s number $Re > 2000$, the flow of fluid is turbulent.
$Reason :$ Inertial forces are dominant compared to the viscous forces at such high Reynold’s numbers.
AIIMS 2005, Easy
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Reynold number $ =\frac{ Inertial force per unit area}{Viscous force perunit area}$ So for higher value of Reynold’s number, inertial force is dominant.
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