For a broad-crested weir, the maximum discharge per unit width occurs when the depth of flow over the crest y_c satisfies:
Choose the correct answer
y_c = H (full upstream head)
y_c = 2H/3 (two-thirds of upstream head = critical depth on crest)
y_c = H/2
y_c = H/4
Correct Answer
B. y_c = 2H/3 (two-thirds of upstream head = critical depth on crest)
AI Detailed Explanation & IS Code Reference
Unlock the reasoning, formula path and code-linked notes inside your student dashboard.
For a broad-crested weir (critical flow on the crest): y_c = 2H/3, where H = upstream head above crest. Maximum q = (2g/3)^(1/2) x (2H/3)^(3/2) = 1.705 H^(3/2) per unit width (ideal). This is the critical flow condition on the horizontal crest.
ScoreCardAI links this solution with subject, topic and difficulty signals so your scorecard can identify weak areas after a full mock test.
Practice more Civil Engineering questions
This MCQ belongs to AE Level Premium Test Series. Full tests include timed attempts, rank comparison and subject-wise analysis.