Free Hydraulics and Water Resources MCQs with Answers
78 Hydraulics and Water Resources MCQs from Civil Engineering, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Hydraulics studies fluid properties, pressure, buoyancy, continuity, Bernoulli's equation, momentum, pipe flow, open-channel flow and hydraulic machines. Water resources extends these principles to pumps, turbines, reservoirs, irrigation, floods and hydrology, while distinguishing laminar from turbulent flow and uniform from gradually varied channel flow.
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78 questions · page 3 of 4
- A. Sudden change in flow velocity
- B. Gradual pipe enlargement
- C. Steady increase in water temperature
- D. Reduction in atmospheric pressure
Explanation: Water hammer is a pressure surge produced when the velocity of flowing water changes rapidly, such as during sudden valve closure.
Correct answer: Sudden change in flow velocity- A. Pump discharge only
- B. Both discharge and head
- C. Pump head only
- D. Neither discharge nor head
Explanation: The pump affinity relationships indicate that discharge varies approximately with impeller diameter squared, while head varies…
Correct answer: Both discharge and head- A. Pelton turbine
- B. Francis turbine
- C. Kaplan turbine
- D. Turgo turbine
Explanation: Kaplan turbines are axial-flow reaction turbines designed for relatively low heads and large discharges.
Correct answer: Kaplan turbine- A. Direct rainfall on the channel
- B. Evaporation from nearby fields
- C. Surface detention on rooftops
- D. Groundwater seepage into the channel
Explanation: Baseflow is the relatively sustained part of streamflow supplied mainly by groundwater discharge and delayed subsurface flow.
Correct answer: Groundwater seepage into the channel- A. One unit of effective rainfall over a specified duration
- B. One unit of total rainfall over an entire year
- C. Constant rainfall of any intensity for one day
- D. Groundwater flow from one observation well
Explanation: A unit hydrograph is the direct runoff response to one unit depth of effective rainfall distributed uniformly over the catchment during a…
Correct answer: One unit of effective rainfall over a specified duration- A. Deep percolation below the root zone
- B. Evapotranspiration by the crop
- C. Runoff leaving the irrigated field
- D. Water stored in the conveyance canal
Explanation: Consumptive use is the water consumed by crop growth and evaporation from the soil and plant surfaces, commonly represented by…
Correct answer: Evapotranspiration by the crop- A. Increasing downstream channel slope
- B. Increasing rainfall over the catchment
- C. Temporarily storing part of the inflow
- D. Eliminating all evaporation losses
Explanation: Flood storage temporarily holds part of the incoming flood volume and releases it at a lower rate over a longer period.
Correct answer: Temporarily storing part of the inflow- A. Controlled only by bed roughness
- B. Uniform throughout the channel length
- C. Equal to atmospheric at every point
- D. Hydrostatic at each section
Explanation: Gradually varied flow changes slowly enough along the channel that vertical accelerations are negligible.
Correct answer: Hydrostatic at each section- A. Weight per unit volume
- B. Mass per unit volume
- C. Volume per unit mass
- D. Weight per unit area
Explanation: Specific weight is the gravitational force or weight contained in a unit volume of fluid.
Correct answer: Weight per unit volume- A. Above the centroid of the surface
- B. Below the centroid of the surface
- C. At the free surface of the liquid
- D. At the lower edge of the surface
Explanation: Pressure increases with depth, so the resultant hydrostatic force acts below the geometric centroid of a vertical plane.
Correct answer: Below the centroid of the surface- A. Pressure head
- B. Elevation head
- C. Velocity head
- D. Friction head
Explanation: The energy grade line represents elevation head plus pressure head plus velocity head.
Correct answer: Velocity head- A. Change in fluid density
- B. Reduction in gravitational acceleration
- C. Increase in atmospheric pressure
- D. Local turbulence and flow separation
Explanation: A sharp bend changes the direction of flow and produces separation, eddies, and turbulence.
Correct answer: Local turbulence and flow separation- A. Four
- B. Two
- C. Six
- D. Eight
Explanation: The pump affinity law states that head varies with the square of rotational speed.
Correct answer: Four- A. Equal to zero
- B. Less than one
- C. Equal to one
- D. Greater than one
Explanation: Subcritical flow has Froude number less than one, meaning gravitational effects dominate inertial effects.
Correct answer: Less than one- A. One-half
- B. One
- C. Three-halves
- D. Two
Explanation: The standard weir relationship for a rectangular sharp-crested weir has discharge proportional to H^(3/2), apart from the coefficient and…
Correct answer: Three-halves- A. Pumped from the source
- B. Returned to the river
- C. Lost through evaporation
- D. Delivered to the field
Explanation: Field irrigation efficiency measures how much of the water delivered to the field is stored in the effective root zone.
Correct answer: Delivered to the field- A. The hydraulically most distant point to reach the outlet
- B. The outlet to reach the watershed divide
- C. The river to reach its bankfull stage
- D. A reservoir to fill to its normal level
Explanation: The time of concentration is the travel time from the hydraulically most distant point in a catchment to its outlet.
Correct answer: The hydraulically most distant point to reach the outlet- A. Mercury at standard conditions
- B. Water at a specified reference condition
- C. Air at standard conditions
- D. The surrounding soil
Explanation: Specific gravity compares a substance's density with the density of a reference substance, commonly water for liquids.
Correct answer: Water at a specified reference condition- A. Friction head
- B. Velocity head
- C. Pressure head
- D. Elevation head
Explanation: A piezometer indicates the pressure head at the connection point as a water column.
Correct answer: Pressure head- A. Distance to its pressure centre
- B. Depth of its top edge
- C. Depth of its bottom edge
- D. Depth of its centroid
Explanation: The resultant hydrostatic force is γA h̄, where h̄ is the vertical depth of the surface centroid below the free surface.
Correct answer: Depth of its centroid