A horizontal venturimeter with an inlet diameter $)=(20(cm)$ and throat diameter $)=(10(cm)$ is used to measure the flow of fluid of specific gravity $)=(0\mathrm{.}8.$ The discharge of fluid through venturimeter is $(Q=0\mathrm{.}06m^{\frac{3}{s}}).$ The specific gravity of the liquid in the U$-$tube manometer is $)=(0\mathrm{.}5.$ Find the reading of the oil$-$mercury differential manometer. Take $C_d=0\mathrm{.}96$