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The diameter of the nozzle (d) for maximum transmission of power is given by (where D = Diameter of pipe, f = Darcys coefficient of friction for pipe, and l = Length of pipe)
d = (D⁵/8fl)1/2
d = (D⁵/8fl)1/3
d = (D⁵/8fl)1/4
d = (D⁵/8fl)1/5