A MOSFET rated for 20 A, carries a periodic current expressed as \(i\left( t \right) = \left\{ {\begin{array}{*{20}{c}} {15,\;\;0 < t < \frac{T}{4}}\\ {0,\;\;\frac{T}{4} < t < T} \end{array}} \right.\).  The on-state resistance of the MOSFET is 0.25 Ω. The average on-state power loss of device for four cycles is ________ (in W)