Final answer:
The pressure of the gas measured with the open-tube mercury manometer is 828 mmHg. This is calculated by adding the atmospheric pressure (736 mmHg) to the mercury level difference (92 mmHg). Both options A and D are correct.
Step-by-step explanation:
The student is asking about the pressure of a gas measured using an open-tube mercury manometer. Atmospheric pressure is given as 736 mmHg, and the difference in mercury level (denoted as 'h') is 92 mmHg. To determine the gas pressure, we add the difference in mercury level to the atmospheric pressure if the mercury level on the side open to the atmosphere is lower than on the gas side of the manometer (which indicates the gas pressure is higher than atmospheric pressure).
In this case, the pressure of the gas is calculated as follows:
Pressure of gas = Atmospheric pressure + h
Pressure of gas = 736 mmHg + 92 mmHg
Pressure of gas = 828 mmHg
This is the gauge pressure, which is the pressure relative to atmospheric pressure. To answer the question, option A is correct. The pressure of the gas is 828 mmHg, which is the same as '828 mmHg (absolute)' because the question implies the measurement is already absolute, so option D would also be considered correct in the context of specifying absolute pressure.