Question

 A constant volume gas thermometer containing helium gives readings of gas pressure, ‘p’ of 1000 and 1366 mm of mercury at the ice point and the steam point respectively.

(a) Express the gas thermometer Celsius temperature, ‘tc’ in terms of gas pressure p.

(b) The thermometer, when left standing in the atmosphere, registers 1075 mm. Determine the

atmospheric temperature.

Answer 1

Solution.

$0^oC - 1000$ mm of mercury;

$100^oC - 1366$ mm of mercury;

$\Delta t=100^oC; \Delta p=366$ mm of mercury;

$\dfrac{\Delta p}{\Delta t}=\dfrac{366 mm of mercury}{100^oC}=3.66\dfrac{mm}{^oC};$

$a) t_C=\dfrac{p-1000}{3.66}(^oC)$ ;

$b) p=1075$ mm of mercury;

$t_c=\dfrac{1075-1000}{3.66}=20.5^oC;$

Answer: $a) t_C=\dfrac{p-1000}{3.66}(^oC)$ ;

$t_c=20.5^oC.$