# Water Resources Engineering (Test 3)

## Gate Exam : Ce Civil Engineering

| Home | | Gate Exam | | Ce Civil Engineering | | Water Resources Engineering | Water Resources Engineering
| Water Resources Engineering |
Q.1
An aerobic reactor receives wastewater at a flow rate of 500 m3d having a COD of 2000 mg/L. The effluent COD is 400 mg/L. Assuming that wastewater contains 80% biodegradable waste, the daily volume of methane produced by the reactor is
A. 0.224 m3
B. 0.280 m3
C. 224 m3
D. 280 m3
Explaination / Solution:
No Explaination.

Workspace
Report
Q.2
Water(γw = 9.879 kN/m3) flows with a flow rate of 0.3 m3 sec through a pipe AB of 10 m length and of uniform cross-section. The end B is above end A and the pipe makes an angle of 30o to the horizontal. For a pressure of 12 N/m2 at the end B, the corresponding pressure at the end A is
A. 12.0 kN/m2
B. 17.0 kN/m2
C. 56.4 kN/m2
D. 61.4 kN/m2
Explaination / Solution:
No Explaination.

Workspace
Report
Q.3
An agricultural land of 437 ha is to be irrigated for a particular crop. The base period of the crop is 90 days and the total depth of water required by the crop is 105 cm. If a rainfall of 15 cm occurs during the base period, the duty of irrigation water is
A. 437 ha/cumec
B. 486 ha/cumec
C. 741 ha/cumec
D. 864 ha/cumec
Explaination / Solution:
No Explaination.

Workspace
Report
Q.4
In the water content of a fully saturated soil mass is 100% the void ratio of the sample is
A. Less than specific gravity of soil
B. equal to specific gravity of soil
C. greater than specific gravity of soil
D. independent of specific gravity of soil
Explaination / Solution:
No Explaination.

Workspace
Report
Q.5
The average surface area of a reservoir in the month of June is 20 km2. In the same month, the average rate of inflow is 10 m3 /s, outflow rate is 15 m3/s, monthly rainfall is 10 cm, monthly seepage loss is 1.8 cm and the storage change is 16 million m3 . The evaporation (in cm) in that month is
A. 46.8
B. 136.0
C. 13.6
D. 23.4
Explaination / Solution: Workspace
Report
Q.6
The flow of water (mass density = 100 kg/m3 and kinematic viscosity = 10-6 m2/s) in a commercial pipe, having equivalent roughness ks as 0.12 mm, yields an average shear stress at the pipe boundary = 600 N/m2. The value of ks/δ' (δ' being the thickness of laminar sub-layer) for this pipe is
A. 0.25
B. 0.50
C. 6.0
D. 8.0
Explaination / Solution:
No Explaination.

Workspace
Report
Q.7
A plane flow has velocity components u = 1/T1, v = -y/T2 and w = 0 and x, y and z directions respectively, where T1 (≠0) and T2 (≠0) are constants having the dimensions of time. The given flow is incompressible if
A. T= -T2
B. T= -T2/2
C. T= T2/2
D. T= T2
Explaination / Solution: Workspace
Report
Q.8
A waste water stream (flow = 2 m3 /s, ultimate BOD = 90 mg/l) is joining a small river (flow = 12 m3 /s, ultimate BOD = 5 mg/l). Both water streams get mixed up instantaneously. Crosssectional area of the river is 50 m2 . Assuming the de-oxygenation rate constant, k' = 0.25/day, the BOD (in mg/l) of the river water, 10 km downstream of the mixing point is
A. 1.68
B. 12.63
C. 15.46
D. 1.37
Explaination / Solution: Workspace
Report
Q.9
Group-I contains dimensionless parameter and Group-II contains ratio Correct match of the dimensionless parameter in Group-I with Group-II is
A. P − 3,Q − 2,R − 4,S − 1
B. P − 3,Q − 4,R − 2,S − 1
C. P − 2,Q − 3,R − 4,S − 1
D. P − 1,Q − 3,R − 2,S − 4
Explaination / Solution:
No Explaination.

Workspace
Report
Q.10
A spillway discharges flood flow at a rate of 9 m3/s per metre width. If the depth of flow on the horizontal apron at the toe of the spillway is 46 cm, the tail water depth needed to form a hydraulic jump is approximately given by which of the following options?
A. 2.54 m
B. 4.90 m
C. 5.77 m
D. 6.23 m