How much is the critical depth in a rectangular channel $2\mathrm{.}5m$ in width and $Q=1\mathrm{.}5\frac{m^3}{s}.$ Use given formulazs and explain.

$Fr=\frac{V}{\sqrt[\phantom{2}]{gy}}$

$y_c=\sqrt[3]{\frac{Q^2}{B^{2}g}}$