SSC JE Mechanical Engineering 2018 Set 3 Paper

The depth of flow at which specific energy is minimum is called critical depth
Specific energy ${\mathit{h}}_{\mathit{c}}={\left(\frac{{\mathit{q}}^2}{\mathit{g}}\right)}^{\frac{1}{3}}$
where q = discharge per unit width
The flow corresponding to critical depth is known as critical. It is maximum when ${\mathit{E}}_{\min }=\frac{3}{2}{\mathit{h}}_{\mathit{c}}$