The discharge through a large rectangular orifice is given by (where H1 = Height of the liquid above the top of the orifice, H2 = Height of the liquid above the bottom of the orifice, b = Breadth of the orifice, and Cd = Coefficient of discharge)

• A. Q = (2/3) Cd × b × √(2g) × (H2 - H1)
• B. Q = (2/3) Cd × b × √(2g) × (H21/2 - H11/2)
• C. Q = (2/3) Cd × b × √(2g) × (H22 - H12)
• D. Q = (2/3) Cd × b × √(2g) × (H23/2 - H13/2)

Answer: (D)