Before mixing begins in a food-processing vat, sunflower oil rests above sugar syrup with a horizontal boundary between them. The vertical distance from the upper surface of the oil to the boundary is 0.25 m, and the sensor in the floor is 0.40 m below the boundary. The density of the sunflower oil is 920 kg/m3 and the density of the sugar syrup is 1250 kg/m3. A second pressure sensor is level with the upper surface and exposed to the same air as the liquids. Take g=10 N/kgg=10\ \mathrm{N/kg}g=10 N/kg. Use p=hρgp=h\rho gp=hρg.
What is the difference between the pressure readings of the two sensors?
6.0 kPa6.0\ \mathrm{kPa}6.0 kPa
8.1 kPa8.1\ \mathrm{kPa}8.1 kPa
5.0 kPa5.0\ \mathrm{kPa}5.0 kPa
7.3 kPa7.3\ \mathrm{kPa}7.3 kPa
132 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.