An orifice plate $($orifice diameter of $124$ mm$)$ is set in a horizontal pipeline $($inside

diameter of $150$ mm$),$ which carries oil of density $877$ kg m$-3.$ If a water manometer is

coupled across the orifice plate, what is the maximum rate at which oil can be

metered through the pipeline if the difference in water levels in the manometer must

not exceed $750$ mm$.$ Assume the discharge coefficient is $0\mathrm{.}6.($Answer: flow rate $=$

$0\mathrm{.}0143$ m$3$ s$-1)$

Hints:

If the maximum difference in water levels in the manometer is $750$ mm$,$ then the

maximum pressure difference is $???$Use the orifice plate equation to work out the flow rate at the maximum pressure

difference.