Question

calculate the pressure of gas in cm of hg in each case ( liquid used is hg) ​

Answer 1

$\sf{\underline{\pink{In \:1^{st} \:Figure}}}$

$\sf\blue{\fbox{Pressure of gas = Height of Hg raised}}$

$\sf{\green{P_{gas} = 100 mm of Hg}}$

$\sf{\underline{\pink{In \:2^{nd} \:Figure}}}$

$\sf\small\small\orange{\fbox{Pressure\: of\: gas\:=\: Atmospheric \:pressure \:-\: Pressure \:of \:height \:of \:Hg \:raised }}$

$\sf{P_{gas} = P_{atm} - 100\:mm\:of\:Hg}$

$\sf{P_{gas} = 760 - 100}$

$\sf\green{P_{gas} = 660 \:mm\: of\: Hg}$

$\sf{\underline{\pink{In \:3^{rd} \:Figure}}}$

$\sf\blue\small\small\orange{\fbox{Pressure\: of\: gas\:=\: Atmospheric \:pressure \:+\: Pressure \:of \:height \:of \:Hg \:raised}}$

$\sf{P_{gas} = P_{atm} + 100\:mm\:of\:Hg}$

$\sf{P_{gas} = 760 + 100}$

$\sf\green{P_{gas} = 860\: mm\: of\: Hg}$