Reynolds number — UPSC CSE 1993 Physics PYQ

Define Reynold's number, the cross sectional radius of a pipeline decreases following the relation. r = r_0 e^{-ax}, where a = 0.6\text{ m}^{-1}, x is the distance (in \text{m}) from the pipeline inlet. Calculate the ratio of Reynold's number for two cross sections separated by \Delta x = 3\text{m}.