A geological engineering firm monitors the pressure of natural gas stored in an underground cavern using a vertical U-shaped shaft filled with brackish water. The difference in the water levels between the two vertical shafts of the U-tube is ddd metres.
During an expansion project, the outer vertical shaft is excavated to double its cross-sectional area, while the inner shaft remains the same. The pressure of the gas and the density of the water do not change.
Explain why the vertical level difference ddd remains unchanged.
54 exam-style questions on Edexcel GCSE Physics 15.2 Pressure in fluids, covering 15.2.1 Atmospheric pressure and height, 15.2.2 Pressure in fluids, 15.2.3 Pressure, force and area, 15.2.4 Pressure and depth, 15.2.5 Pressure in liquids: depth and density, 15.2.6 Upthrust, and 15.2.7 Floating and sinking. Each one has a worked solution and a mark scheme showing where the marks go.