Question

A tank with a small hole at the bottom has been filled with water and kerosene (specific gravity $0.8$). The height of water is $3m$ and that of kerosene $2m$. When the hole is opened the velocity of fluid coming out from it is nearly : (take $g=10m{s}^{-2}$ and density of water $={10}^{3}kg{m}^{-3})$

• A. $8.5m{s}^{-1}$
• B. $9.6m{s}^{-1}$
• C. $10.7m{s}^{-1}$
• D. $7.6m{s}^{-1}$

Answer 1

The correct option is B $9.6m{s}^{-1}$

From Torricelli's equation,

${\rho }_k\times g\times h_k+{\rho }_w\times g\times h_w=\frac{1}{2}\times \rho \times v^2$

$\therefore (0.8\times 2+1\times 3)\times 9.81=\frac{1}{2}\times 1\times v^2$

$\therefore v=9.6m/s$