Question

In the given figure, atmospheric pressure $p_0=1atm$ and mercury column length is $9cm$. Pressure $p$ of the gas enclosed in the tube is:

• A. pressure of $67cm$ of $Hg$
• B. pressure of $90cm$ of $Hg$
• C. pressure of $78cm$ of $Hg$
• D. pressure of $85cm$ of $Hg$

Answer 1

The correct option is D pressure of $85cm$ of $Hg$

Given,
Atmospheric pressure $\left(P_0\right)=1atm=76cm$ of $Hg$
Length of mercury column $\left(P^{\prime }\right)=9cm$
We know that, $p_{gas}=p_{atm}+p^{\prime }$
$p_{gas}=76cm$ of $Hg+9cm$ of $Hg$
$p_{gas}=85cm$ of $Hg$.