Consider a wind turbine generator which has following basic design characteristics given below. Calculate tip-speed ratio of this wind turbine generator.(Mark the closest answer) Parameter Value Units k 2.15 C 8.9 Blade diameter 50 m Rated wind speed 12.5 m/s Cut-in speed 5.25 m/s Furling speed 25 m/s Blade tip loss 30% Efficiency (electrical and frictional losses) 70% Coefficient of performance 0.42 Air density 1.2 Kg/m3 Blade speed 26 rpm O 6.2 O 5.0 O 5.6 O 5.4 O 4.2