An open channel of symmetric right-angled triangular cross-section is conveying a discharge āQā. Taking āgā as the acceleration due to gravity, what is the critical depth?
1
\( {(\frac{Q^2}{g}}) ^{1/3}\)
2
\( {(\frac{Q^2}{g}}) ^{1/5}\)
3
\( {(\frac{2Q^2}{g}}) ^{1/5}\)
4
\( {(\frac{2Q^2}{g}}) ^{1/3}\)