Correct Answer - Option 2 : minimum
Explanation:
For a given value of specific energy, the critical depth gives the greatest discharge, or conversely, for a given discharge, the specific energy is a minimum for the critical depth.
For rectangular channels, the critical depth,
dc(m), is given by
\({d_c} = {\left[ {\frac{{{Q^2}}}{{{b^2}g}}} \right]^{\frac{1}{3}}}\)
Where dc = critical depth (in m), Q = quantity of flow or discharge (in m3/s), B = Width of channel (in m)
