All Free Civil Engineering MCQs with Answers

• 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.

• 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…

• 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.

• 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.

• 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…

• 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…

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

• A. Four
• B. Two
• C. Six
• D. Eight

Explanation: The pump affinity law states that head varies with the square of rotational speed.

• 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.

• 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…

• 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.

• 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.

• 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.

• 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.

• 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.