For maximum diagram efficiency.

Question

In a simple impulse turbine the nozzle angle at the entrance is 30⁰. For maximum diagram efficiency. The blade – stepped ratio is (note : sin 30⁰= 0.5, cos 30⁰= 0.866 sin 15⁰= 0.259, cos 15⁰=0.966)  

(a)0.259                       (b)0.75

(c) 0.5                          (d)0.433