An impulse stage of a steam turbine has a mean ‘diameter of 12 m. The speed of the rotor is 3000 r.p.m. The mass flow rate of steam is 20 kg/s. Steam is supplied to the stage at 15 kg/cm2 and 300°C where it expands to 10 kg/cm2. Determine the efficiency and the power output of the stage if the nozzle efficiency is 0.9 and the blade velocity coefficient is 0.92. Assume acceleration from rest for the steam expanding in the nozzle. Assume nozzle angle to be 25°.