Question 1 Report
The diagram shows a mercury manometer connected between two gas supplies P and Q. The mercury stands higher on the P side. Which gas is at the LOWER pressure?
The gas at the lower pressure is gas P. In a manometer the mercury is pushed down on the high-pressure side and rises on the low-pressure side; since the mercury stands higher on the P side, P is pushing less hard than Q. So Q is at the higher pressure and P the lower. The pressures are clearly not equal (the levels differ by \(h\)) and they can be compared directly from that difference.
Everything you need to excel in your exams