Hydraulic Machines MCQ with answer and solution

Concept

A surge moves with speed relative to the flowing water. Its absolute speed changes with the direction of the stream flow.

Step-by-step solution

1. Let V₁/V_s = 0.8, so V₁ = 0.8 V_s. 2. Direct use of relative speeds gives (V_s + V₁)/(V_s - V₁) = 1.8/0.2 = 9, which is not an option. 3. The question wording is unclear, so none of my readings gives a clean match with the options. 4. The only simple link between 0.8 and the options is the reciprocal 1/0.8 = 1.25.

Explanation

A surge is a moving wave whose speed is measured relative to the water. When it moves against the stream, the relative speed is larger than when it moves with the stream. The exact ratio depends on how 'celerity' is defined in the source, and the question does not say.