250+ TOP MCQs on Manning’s Equation – 1 and Answers

Fluid Mechanics Multiple Choice Questions on “Manning’s Equation – 1”.

1. A rectangular channel is having depth 2m and width 3m, bed slope of 1 in 700. The value of manning’s roughness co efficient (n) is 0.06, estimate the discharge through the channel.
a) 2.42m³⁄s
b) 3.42m³⁄s
c) 4.42m³⁄s
d) 5.42m³⁄s
Answer: b
Clarification:

2. Estimate the discharge through a triangular channel having depth 7m and side slope 1H:5V in which the bed slope is 1 in 1000. Manning’s co efficient = 0.03.
a) 8.07m³⁄s
b) 9.07m³⁄s
c) 10.07m³⁄s
d) 11.07m³⁄s
Answer: a
Clarification:

3. The base width and the depth of a trapezoidal channel is 9m and 5m respectively. Calculate the discharge through a channel if the side slope of the channel is 1H:4V and the bed slope is 1 in 500. (n=0.04)
a) 109.73m³⁄s
b) 110.73m³⁄s
c) 111.73m³⁄s
d) 112.73m³⁄s
Answer: a
Clarification:

4. A circular channel section has diameter of 6m and it is running half. Calculate the discharge through the channel if the bed slope is 1 in 600 and manning’s co efficient is equal to 0.014.
a) 52m³⁄s
b) 53m³⁄s
c) 54m³⁄s
d) 55m³⁄s
Answer: c
Clarification:

5. The diameter of a circular channel section which is running full is 8m. Determine the discharge through the channel section if the bed slope is 1 in 600 and the value of the manning’s co efficient is 0.013.
a) 249.45m³⁄s
b) 250.45m³⁄s
c) 251.45m³⁄s
d) 252.45m³⁄s
Answer: b
Clarification:

6. The area of a channel section is 8m² and the wetted perimeter is 8m. Calculate the value of the bed slope of the channel if the discharge is 33.33m³⁄s and manning’s co efficient is 0.012.
a) 1 in 300
b) 1 in 400
c) 1 in 500
d) 1 in 600
Answer: b
Clarification:

7. The area of the triangular section is 66.67m² and the wetted perimeter of the section is 24.03m. Calculate the value of the manning’s roughness co efficient if the bed slope of the channel section is 1 in 500 and the discharge through the channel is 117.61m³⁄s.
a) 0.03
b) 0.04
c) 0.05
d) 0.06
Answer: c
Clarification:

8. The discharge through a trapezoidal channel is 245.06m³⁄s and the bed slope is 1 in 1000. Calculate the value of the wetted area if the hydraulic radius is 2.26m. Manning’s roughness co efficient = 0.008.
a) 34m²
b) 35m²
c) 36m²
d) 37m²
Answer: c
Clarification:

9. Determine the value of manning’s constant for a rectangular channel if Chezy’s constant is equal to 50 and the depth and widths of the channel are 4m and 7m respectively.
a) 0.012
b) 0.022
c) 0.032
d) 0.042
Answer: b
Clarification:

10. The side slope of a triangular channel section is 1H:4V and the depth is 12m. Calculate the value of chezy’s constant if the value of manning’s constant is 0.03.
a) 32.48
b) 33.48
c) 34.48
d) 35.48
Answer: d
Clarification:

11. Determine the value of Chezy’ s constant for a trapezoidal channel having depth 3m, base width 11m, side slope 1H:3V and the manning’s co efficient is 0.012.
a) 94.15
b) 94.25
c) 94.35
d) 94.45
Answer: a
Clarification:

12. Estimate the value of the manning’s constant for a fully running circular section having diameter of 8m and the value of Chezy’s constant is 50.
a) 0.022
b) 0.032
c) 0.042
d) 0.052
Answer: a
Clarification:

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