The density of the atmosphere at sea level is $1.29 \; kg/m^3$. Assume that it does not change with altitude. Then how high (in $km$) would the atmosphere extend?

What is atmospheric pressure?

Two liquids having densities $d_1$ and $d_2$ are mixed in such a way that both have the same mass. The density of the mixture is ............

Explain the specific density or relative density of a substance.

$A$ $U$-tube having a horizontal arm of length $20 \ cm$ has a uniform cross-sectional area of $1 \ cm^2$. It is filled with water of volume $60 \ cc$. What volume of a liquid of density $4 \ g/cc$ should be poured from one side into the $U$-tube so that no water is left in the horizontal arm of the tube? (Answer in $cc$)

Explain the pressure-measuring device at any point in a fluid in short.