Question

The hydraulic efficiency of an impulse turbine is maximum when the velocity is …………. of the jet velocity.

• A. {One-fourth}
• B. {Three-fourth}
• C. {One-half}
• D. {Double}

Hint:

For maximum efficiency in an impulse turbine, the blade speed should be half of the jet velocity.

Answer 1

The Correct Option is C

Step 1: The hydraulic efficiency \( \eta_h \) of an impulse turbine is given by: \[ \eta_h = \frac{2u(V - u)}{V^2} \] where: - \( u \) is the blade velocity, - \( V \) is the jet velocity. 
Step 2: The efficiency is maximum when \( u = \frac{V}{2} \). Thus, the correct answer is (C) One-half.