The discharge through a large rectangular orifice is
Where b = Width of the orifice
H1 = height of the liquid above top edge of orifice
H2 = height of liquid above bottom edge of orifice
Cd = coefficient of discharge
1
\(\frac{2}{3}{C_d}\space .\space b\sqrt {2g}\space (\sqrt {H_2} - \sqrt {H_1} )\)
2
\(\frac{8}{{15}}{C_d}\space.b\space\sqrt {2g} \space(H_2^{3/2} - H_1^{3/2})\)
3
\(\frac{2}{3}{C_d}\space .\space b\sqrt {2g}\space (H_2^{3/2} - H_1^{3/2})\)
4
None of the above