Assertion A.: The minimum self cleansing velocity in the sewer, at least once a day, must be generated. Reason (R): If certain deposition takes place and is not removed, it obstructs free flow and causes further deposition leading to complete blocking of the sewer?

Related Mcqs:

1. You are asked to design sewer pipes of diameters 0.4 m to 0.9 m at maximum flow, you will assume the sewer flow running at___________________?

   A. Full depth
   B. Half full
   C. Two third full
   D. Three fourth full

2. Assertion A.: The determination of pH value of sewerage is important. Reason (R): The efficiency of certain treatment methods depends upon the availability of pH value________________?

   A. Both A and R are true and R is the correct explanation of A
   B. Both A and R are true but R is not a correct explanation of A
   C. A is true but R is false
   D. A is false but R is true

3. Assertion A.: A free board of 0.3 m is provided above the top sewage line in septic tanks. Reason (R): It helps to accommodate the scum in the septic tank_________________?

   A. Both A and R is true and R is the correct explanation of A
   B. Both A and R is true but R is not a correct explanation of A
   C. A is true but R is false
   D. A is false but R is true

4. The angle subtended by the surface of sewer water with partial flow, at sewer centre is 120°, the depth of sewerage is________________________?

   A. 20 cm
   B. 25 cm
   C. 40 cm
   D. 50 cm

5. A sewer pipe contains 1 mm sand particles of specific gravity 2.65 and 5 mm organic particles of specific gravity 1.2, the minimum velocity required for removing the sewerage, is_____________________?

   A. 0.30 m/sec
   B. 0.35 m/sec
   C. 0.40 m/sec
   D. 0.45 m/sec

6. In Chezy’s formula V = C rs for calculating the velocity of flow in circular sewer of diameter running full, the value of hydraulic mean radius is_______________?

   A. D
   B. D /2
   C. D/3
   D. D/4

7. If is the rugosity coefficient, is the bed slope of sewer, the velocity of flow in m/sec may be obtained by the formula V = (1/n) r2/3 s1/2 evolved by_________________?

   A. Chezy
   B. Manning
   C. Bazin
   D. Kutter

8. If the flame of a miner’s safety lamp in the upper layers of the sewer forms an explosive, the sewer certainly contains_______________?

   A. Hydrogen sulphide
   B. Carbon dioxide
   C. Methane
   D. Oxygen

9. If the discharge of a sewer running half is 628 1.p.s., i = 0.001, and n = 0.010, the diameter of the sewer, is__________________?

   A. 1.39 m
   B. 1.49 m
   C. 1.59 m
   D. 1.69 m

10. The width of a rectangular sewer is twice its depth while discharging 1.5 m/sec. The width of the sewer is______________?

    A. 0.68 m
    B. 0.88 m
    C. 1.36 m
    D. 1.76 m