Question

In the given figure, atmospheric pressure $p_0=1$ atm and mercury column length is $9cm$ . 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 $\left(p_0\right)=1atm=76cm$ of $\text{Hg}$
Pressure due to mercury column $\left(p^{\prime }\right)=9cm$ of $\text{Hg}$

We know that, $p_{\text{gas}}=p_{\text{atm}}+p^{\prime }$
$p_{\text{gas}}=76cm$ of $Hg+9cm$ of $Hg$ $p_{gas}=85cmofHg$