The discharge through a small rectangular orifice is given by
where, C = Coefficient of discharge for the orifice,
a = cross-sectional area of the orifice,
h = height of the liquid above the centre of the orifice
1
\(Q = {C_d} \times a \times \sqrt {2gh} \)
2
\(Q = \frac{2}{3}{C_d} \times a \times h\)
3
\(Q = \frac{{3{C_d} \times a}}{{\sqrt {2gh} }}\)
4
\(Q = \frac{{{C_d} \times a}}{{\sqrt {2gh} }}\)