Two ideal gas thermometers A and B use oxygen and hydrogen respectively. The following observations are made :

What do you think is the reason behind the slight difference in answers of thermometers A and B ? (The thermometers are not faulty). What further procedure is needed in the experiment to reduce the discrepancy between the two readings ?

Explanation

The reason of minor difference in answer is that in reality hydrogen and oxygen are not ideal gases.
To reduce the discrepancy, readings should be taken for lower and lower pressure and plot between temperature measured versus absolute pressure of the gas at tripple point should be extra ploted to obtain temperature in the limit pressure trends to zero, when the gases approach ideal gas behaviour.