Orifices are commonly placed in flow lines to measure the flow rate through the line. The flow rate is proportional to the square root of the pressure decrease across the orifice. The mercury manometer shown here is used to measure this pressure decrease between points A and B at the pipe wall. Answer the questions below for h1 = 19.4 cm and h2 = 3.39 cm. What is the orifice pressure decrease in cm of water?