This set of Environmental Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Hydraulic Elements of Circular Sewers”.

1. Which of the following is incorrect regarding circular sewer?

a) It is easily manufactured

b) It offers more opportunities for deposits

c) It is the most economical section

d) It has uniform curvature

View Answer

Explanation: The circular section has uniform curvature, so it offers less opportunities for deposits.

2. A circular section of sewer gives _______ area for a given perimeter.

a) Small

b) Large

c) Minimum

d) Maximum

View Answer

Explanation: A circular section of sewer gives a maximum area for a given perimeter and gives the greatest hydraulic mean depth when running full or half.

3. What is the wetted perimeter of a circular section of sewer?

a) (22/7) *D^{2}

b) (22/7) *D

c) (22/7) *D^{2}

d) (22/7)^{2} *D

View Answer

Explanation: The wetted perimeter of a circular section of sewer running full is (22/7) *D where D is the internal diameter of circular sewer.

4. The hydraulic mean depth of a circular section running full is __________

a)`D

b) D/2

c) D^{2}

d) D/4

View Answer

Explanation: The hydraulic mean depth, R = Area of cross section / Wetted perimeter

= ((22/7) *D

^{2}/4) / (22/7) *D

= D/4.

5. The proportional depth of a circular sewer running partially half is __________

a) (1-cosK/2)

b) (1/2) * (1-sinK/2)

c) (1/2) * (1-cosK/2)

d) (1-cosK/2)^{2}

View Answer

Explanation: Depth of flow d = (D/2) * (1-cosK/2)

Proportional depth = Depth of flow d / Diameter of section D = (D/2) * (1-cosK/2) / D

= (1/2) * (1-cosK/2).

6. The proportional perimeter of a circular sewer running partially half where K is the central angle subtended at a circular section of sewer is __________

a) K/360^{o}

b) K/90^{o}

c) K/270^{o}

d) K/180^{o}

View Answer

Explanation: Proportional perimeter of a circular sewer running partially half =

(22/7) *D*K/360

^{o}/ ((22/7) *D) = K/360

^{o}.

7. The diameter of the circular sewer is 0.2m. The desired depth of flow is __________

a) 2/3 of the circular section of sewer

b) 1/3 of the circular section of sewer

c) 1/2 of the circular section of sewer

d) 1/4 of the circular section of sewer

View Answer

Explanation: When the diameter of the sewer is up to 0.4m, they are designed to flow at 1/2 depth.

8. The diameter of a circular sewer is 0.8m. The desired depth of flow is __________

a) 2/3 of the circular section of sewer

b) 1/3 of the circular section of sewer

c) 1/2 of the circular section of sewer

d) 1/4 of the circular section of sewer

View Answer

Explanation: When the diameter of the sewer is between 0.4m and 0.8m, they are designed to flow at 2/3 depth.

9. A circular sewer having 0.4m diameter is flowing with velocity 2m/Sec. If the gradient of sewer is 1 in 90. Find the value of Chezy’s coefficient?

a) 10

b) 30

c) 60

d) 40

View Answer

Explanation: Hydraulic mean depth, R = D/4 = 0.4/4 = 0.1m

Slope of sewer S = 1/100, velocity V = 1m/Sec

According to Chezy’s formula, V = C (RS)

^{1/2}= C* (0.1/90)

^{1/2}= C/30

C = V*30 = 2*30 = 60.

**Sanfoundry Global Education & Learning Series – Environmental Engineering.**

To practice all areas of Environmental Engineering, __here is complete set of 1000+ Multiple Choice Questions and Answers__.

**If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]**

**Related Posts:**

- Apply for 1st Year Engineering Internship
- Check Environmental Engineering Books
- Check Mining Engineering Books
- Practice Mining Engineering MCQs