Question

In the given figure, atmospheric pressure $p_{0}=1$ atm and mercury column length is $9 \, cm$ . Pressure $p$ of the gas enclosed in the tube is

• A. Pressure of $67 \, \, \text{cm}$ of $\text{Hg}$
• B. Pressure of $90 \, \, \text{cm}$ of $\text{Hg}$
• C. Pressure of $78 \, \, \text{cm}$ of $\text{Hg}$
• D. Pressure of $85 \, \, \text{cm}$ of $\text{Hg}$

Answer 1

Answer: (D)

Given,
Atmospheric pressure $\left(p_{0}\right)=1 \, atm=76 \, cm$ of $\text{Hg}$
Pressure due to mercury column $\left(p^{′}\right)=9 \, cm$ of $\text{Hg}$

We know that, $p_{\text{gas}}=p_{\text{atm}}+p^{′}$
$p_{\text{gas}}=76 \, cm $ of $ Hg+9 \, cm $ of $Hg$ $p_{g a s}=85 \, cm \, of \, Hg$