Question

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)
A. Vb = 0.5 V cos α
B. Vb = V cos α
C. Vb = 0.5 V2 cos α
D. Vb = V2 cosα

Answer 1

I Think the answer is option A Vb = 0.5 V cos a.

Answer 2

option A.................