SSC JE Mechanical Engineering 27 Oct 2020 Shift 2 Papers

Given, Specific gravity of oil = 0.9
Density of oil, ρ = 0.9 × density of water $=0.9\times 1000=900$ kg/m${}^3$
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
${\left(\mathit{\rho }\mathit{g}\mathit{h}\right)}_{\mathrm{oil}}={\left(\mathit{\rho }\mathit{g}\mathit{h}\right)}_{\mathrm{water}}$
$900\times 9.81\times 40=1000\times 9.81\times \mathit{h}$
∴ h = 36 m of water column