$A$ liquid boils when its vapour pressure equals

Variation of atmospheric pressure with height from the Earth is ................

$A$ container of height $10 \, cm$ is filled with water. There is a hole at the bottom. Find the pressure difference between points at the top and the bottom.

$A$ healthy adult of height $1.7 \,m$ has an average blood pressure $(BP)$ of $100 \,mm$ of $Hg$. The heart is typically at a height of $1.3 \,m$ from the foot. Take the density of blood to be $10^3 \,kg/m^3$ and note that $100 \,mm$ of $Hg$ is equivalent to $13.3 \,kPa$ (kilo pascals). The ratio of $BP$ in the foot region to that in the head region is close to:

$A$ submarine is designed to withstand an absolute pressure of $100 \text{ atm}$. How deep can it go below the water surface (in $\text{ m}$)? (Consider the density of water = $1000 \text{ kg/m}^3$, $1 \text{ atm} = 1 \times 10^5 \text{ Pa}$, and gravitational acceleration $g = 10 \text{ m/s}^2$)

Mention two instruments which measure the atmospheric pressure.