17593. The efficiency of an impulse turbine is maximum when (where Vb = Blade speed, V = Absolute velocity of steam entering the blade, and α = Nozzle angle) September 13, 2025 by Admin Vb = 0.5 V cos α Vb = V cos α Vb = 0.5 V2 cos α Vb = V2 cosα ✅ The correct answer is option A.