Q$4-)$ Air flows through a pipe at a rate of $200\frac{L}{s}.$ The pipe consists of two sections of diameters $20cm$ and $10cm$ with a smooth reducing section that connects them. The pressure difference between the two pipe sections is measured by a water manometer. Neglecting frictional effects, determine the differential height of water between the two pipe sections. ${}_{\text{a}\text{i}\text{r}}=1\mathrm{.}20k\frac{g}{m^3},{}_{\text{w}\text{a}\text{t}\text{e}\text{r}}=1000k\frac{g}{m^3}$