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Rectangular notch (weir) discharge formula For a sharp-crested rectangular notch of width b with head H above the sill and coefficient of discharge C<sub>d</sub>, select the correct standard expression for discharge.

Difficulty: Easy

Q = (2/3) C_d b √(2g) H^3/2
Q = C_d b √(2g) H²
Q = (2/3) C_d b (2g) H^3/2
Q = (2/3) C_d b √(2g) H

Correct Answer: Q = (2/3) C_d b √(2g) H^3/2

Explanation:

Given data

Width = b, head over sill = H, discharge coefficient = C_d.

Concept/Approach

Discharge over a sharp-crested rectangular notch is obtained by integrating elementary strips across the head.

Result
Q = (2/3) C_d b √(2g) H^3/2

Final Answer
(2/3) C_d b √(2g) H^3/2

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