Chapter 3, Problem 3B.2E

Interpretation Introduction

Interpretation:

Pressure of the gas when air trapped has been reduced to $6.85\text{in}$ has to be determined.

Concept Introduction:

Pressure of an atmosphere can be measured through manometer by employing the relation as follows:

  $P=dhg$

Here,

$d$ is density

$h$ is height of mercury.

$g$ is acceleration of free fall.

Manometer is a device as barometer employed to measure pressure of gas trapped in container. Weight of $\text{Hg}$ in glass tube is balanced as per weight of air in atmosphere. Weight of $\text{Hg}$ in glass tube increases until it becomes equal to atmospheric pressure which is nothing but weight of air itself above the reservoir. As soon as equilibrium is reached between weight of both $\text{Hg}$ and air, height of mercury in vertical column is taken as measure of pressure.