An oil of specific gravity 0.9 contained in a vessel. At a point the height of oil is 40 m and for the density of water = 1000 kg/m³, the corresponding height of water at the point will be

Concept:

Hydrostatic pressure of fluid is given by,

P = ρgh

Where, ρ = Density of fluid, g = Acceleration due to gravity and h =  height of water surface

Calculation:

Given, Specific gravity of oil = 0.9

Density of oil, ρ = 0.9 × density of water = 0.9 × 1000 = 900 kg/m³
This is solved by using Pascal’s Law, which states that pressure at all the points in a horizontal direction will be same.

Pressure due to oil height = pressure due water height

\(\begin{array}{l} {\left( {ρ gh} \right)_{oil}} = {\left( {ρ gh} \right)_{water}}\\ 900 \times 9.81 \times 40 = 1000 \times 9.81 \times h \end{array}\)