💧 100 Hydraulic Machines MCQs with Answers (Pumps & Turbines) – Practice Test

Practice Hydraulic Machines MCQs with answers covering pumps, turbines, and fluid mechanics concepts

Attempt all 100 questions, choose the correct option, and check your live score instantly at the end

Question 1: In a Pelton wheel, if the jet velocity remains constant but bucket speed slightly exceeds the optimum value, the hydraulic efficiency will:

Question 2: Cavitation in centrifugal pumps is avoided when:

Question 3: In a Francis turbine operating under part-load conditions, the flow separation mainly occurs at:

Question 4: The specific speed of a centrifugal pump increases when:

Question 5: The main function of a draft tube in reaction turbines is to:

Question 6: In a Pelton turbine, the jet ratio is defined as:

Question 7: Negative slip in a reciprocating pump occurs when:

Question 8: In Kaplan turbines, the flow through the runner is primarily:

Question 9: In centrifugal pumps, priming is necessary to:

Question 10: The governing of a Pelton turbine is achieved by:

Question 11: The manometric efficiency of a centrifugal pump is defined as:

Question 12: Cavitation in turbines is most severe at:

Question 13: In a centrifugal pump, casing is designed to:

Question 14: The turbine best suited for low head and high discharge is:

Question 15: The minimum starting speed of a centrifugal pump depends mainly on:

Question 16: In a Francis turbine, water enters the runner in:

Question 17: In reciprocating pumps, air vessels are used to:

Question 18: Which turbine uses both pressure and kinetic energy?

Question 19: The slip factor in centrifugal pumps accounts for:

Question 20: Draft tube is not used in:

Question 21: In centrifugal pumps, head developed is proportional to:

Question 22: The unit quantity of a turbine is defined as:

Question 23: Cavitation number is used to predict:

Question 24: In a Pelton wheel, braking jet is used to:

Question 25: Specific speed of a turbine is useful for:

Question 26: In a Pelton turbine, if the coefficient of velocity of the nozzle decreases due to wear, while maintaining constant head, the most significant effect will be:

Question 27: A centrifugal pump designed for a specific speed operates at lower discharge than design condition; which phenomenon is most likely responsible for efficiency drop?

Question 28: In a Francis turbine, if the runner blade angle at outlet is improperly designed, the primary consequence will be:

Question 29: For a centrifugal pump, the relationship between head (H) and speed (N) under similarity laws is:

Question 30: In Kaplan turbines, simultaneous adjustment of guide vanes and runner blades ensures:

Question 31: In a draft tube, if flow separation occurs, the most direct impact is:

Question 32: The slip factor in centrifugal pumps becomes significant when:

Question 33: In reciprocating pumps, the effect of acceleration head is most significant when:

Question 34: In Pelton turbines, if jet deflection angle is less than ideal value, the efficiency decreases because:

Question 35: Cavitation parameter (Thoma’s coefficient) is primarily used to:

Question 36: In a centrifugal pump, increasing impeller diameter while keeping speed constant results in:

Question 37: In a Francis turbine, if guide vane angle is not properly matched with runner inlet angle, it leads to:

Question 38: In reciprocating pumps, air vessels reduce power requirement by:

Question 39: For geometrically similar turbines, specific speed remains constant when:

Question 40: In Kaplan turbine operation, cavitation is minimized by:

Question 41: The hydraulic efficiency of a Pelton turbine is maximum when outlet whirl velocity is:

Question 42: In centrifugal pumps, the best efficiency point (BEP) corresponds to:

Question 43: In a draft tube, the angle of divergence is limited to avoid:

Question 44: In a Pelton wheel, increasing number of jets primarily results in:

Question 45: In centrifugal pumps, cavitation can be reduced by:

Question 46: In Francis turbine, specific speed increases with:

Question 47: In reciprocating pumps, separation of liquid occurs when:

Question 48: In Kaplan turbine, runner blades are designed to:

Question 49: In centrifugal pumps, mechanical efficiency is defined as:

Question 50: In turbine operation, runaway speed refers to:

Question 51: In a Pelton turbine, if the jet is not tangential to the wheel but slightly inclined, the primary effect will be:

Question 52: In a centrifugal pump, if the impeller vane outlet angle is increased, keeping other parameters constant, the theoretical head will:

Question 53: In a Francis turbine, if the draft tube is suddenly removed, the most immediate consequence is:

Question 54: In reciprocating pumps, the effect of frictional head losses is most critical during:

Question 55: In Kaplan turbines, if blade pitch mechanism fails and blades remain fixed, the turbine behaves similar to:

Question 56: In centrifugal pumps, recirculation losses become dominant when operating:

Question 57: The governing mechanism of a Francis turbine primarily controls:

Question 58: In Pelton turbine design, if the bucket spacing is too small, it will result in:

Question 59: In centrifugal pumps, the effect of increasing speed on power requirement is governed by:

Question 60: In a reaction turbine, the pressure at runner exit is typically:

Question 61: In a multi-stage centrifugal pump, the arrangement of impellers in series primarily results in:

Question 62: In a Francis turbine, cavitation is influenced most by:

Question 63: In reciprocating pumps, if delivery valve closes late, it causes:

Question 64: In Pelton turbines, braking jet is directed:

Question 65: In centrifugal pumps, the hydraulic efficiency is mainly affected by:

Question 66: In Kaplan turbines, cavitation is most likely near:

Question 67: In centrifugal pumps, the volute casing is designed such that:

Question 68: In a Pelton turbine, if jet diameter is increased keeping head constant, the power developed will:

Question 69: In a Francis turbine, runaway speed is higher because:

Question 70: In reciprocating pumps, separation of liquid can be avoided by:

Question 71: In centrifugal pumps, the minimum starting speed is achieved when:

Question 72: In Kaplan turbines, blade angle adjustment is required because:

Question 73: In Pelton turbines, maximum efficiency occurs when velocity ratio is approximately:

Question 74: In centrifugal pumps, surge phenomenon is associated with:

Question 75: In a Francis turbine, spiral casing is designed to:

Question 76: In reciprocating pumps, indicator diagram represents:

Question 77: In centrifugal pumps, impeller vanes are backward curved because:

Question 78: In Pelton turbines, number of buckets is mainly determined by:

Question 79: In Kaplan turbine, hub diameter is kept large to:

Question 80: In centrifugal pumps, net positive suction head required (NPSHr) depends on:

Question 81: In Francis turbine, efficiency reduces at part load due to:

Question 82: In reciprocating pumps, cavitation is most likely during:

Question 83: In Pelton turbines, specific speed is low because:

Question 84: In centrifugal pumps, cavitation damage is mainly observed on:

Question 85: In Kaplan turbines, flow regulation is achieved by:

Question 86: In centrifugal pumps, shut-off head corresponds to:

Question 87: In Pelton turbine, jet velocity is proportional to:

Question 88: In Francis turbine, guide vanes are used to:

Question 89: In reciprocating pumps, volumetric efficiency decreases due to:

Question 90: In centrifugal pumps, diffuser type casing improves efficiency by:

Question 91: In Pelton turbines, bucket shape is designed to:

Question 92: In Kaplan turbines, cavitation coefficient depends on:

Question 93: In centrifugal pumps, priming is essential because:

Question 94: In Francis turbine, runner blades are designed for:

Question 95: In reciprocating pumps, speed is limited due to:

Question 96: In centrifugal pumps, head-discharge curve is typically:

Question 97: In Pelton turbines, spear valve is used to:

Question 98: In Kaplan turbines, efficiency remains high over wide range because:

Question 99: In centrifugal pumps, power input increases with discharge due to:

Question 100: In hydraulic turbines, overall efficiency is defined as:

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💧 100 Hydraulic Machines MCQs with Answers (Pumps & Turbines) – Practice Test

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