$A$ tank $5 \ m$ high is half-filled with water and then is filled to the top with oil of density $0.85 \ g/cm^3$. The pressure at the bottom of the tank,due to these liquids is ....... $g \ dyne/cm^2$.

$A$ liquid $X$ of density $3.36 \, g/cm^3$ is poured into a $U$-tube containing $Hg$ up to a height of $10 \, cm$. Another liquid $Y$ is poured into the left arm to a height of $8 \, cm$. The upper levels of $X$ and $Y$ are at the same height. Find the density of liquid $Y$ in $g/cm^3$. (Density of $Hg = 13.6 \times 10^3 \, kg/m^3$)

The term 'fluid' is used for ............

The Sun is a hot plasma (ionized matter) with its inner core at a temperature exceeding $10^{7} \; K$,and its outer surface at a temperature of about $6000 \; K$. At these high temperatures,no substance remains in a solid or liquid phase. In what range do you expect the mass density of the Sun to be,in the range of densities of solids and liquids or gases? Check if your guess is correct from the following data: mass of the Sun $= 2.0 \times 10^{30} \; kg$,radius of the Sun $= 7.0 \times 10^{8} \; m$.

Three different liquids are filled in a $U$-tube as shown in the figure. Their densities are $\rho_1, \rho_2$ and $\rho_3$ respectively. From the figure, we may conclude that:

Define pressure. Give the $SI$ and $CGS$ unit of pressure.