1. What is the recommended diameter of a domestic sewer pipe laid at gradient 1 in 100?

1. 100 mm
2. 50 mm
3. 175 mm
4. 150 mm

2. If the slopes of two sewers A and B of same size are 1 in 100 and 1 in 400 respectively, the ratio of velocity of flow in the two sewers A and B will be

1. 1
2. 0.5
3. 2^2/3
4. 2

3. If D is the diameter of upper circular portion, the overall depth of New Egg shaped sewer section is

1. 1.350 D
2. 1.250 D
3. 1.625 D
4. 1.425 D

4. The minimum diameter for public sewer in hilly areas where steep slopes are prevalent is

1. 150
2. 3000
3. 20
4. 100

5. For taking sewer line below road/canal/railway line, following type or sewer appurtenances should be provided

1. Storm water relief work
2. Siphon spillways
3. Jumping weir
4. Inverted syphon

6. The best sewer material to resist hydrogen sulphide corrosion is

1. glazed stone ware
2. reinforced cement concrete
3. asbestos cement
4. none of these

7. The diameter of a RCC sewer pipe is 300mm. The gradient required to generate self cleansing velocity would be of the order of

1. 1 in 190
2. 1 in 100
3. 1 in 920
4. 1 in 220

8. Laying of sewers is usually done with the help of

1. a theodolite
2. a compass
3. a plane table
4. sight rails and boning rods

9. Sewer pipes are made of

1. stone ware
2. earthen ware
3. terracotta
4. refractory ware

10. Crown corrosion in sewer is caused due to the presence of

1. Bromide
2. Nitrate
3. Chloride
4. Sulphate

11. In stoneware pipe glazing is made for

1. waterproofing
2. softening
3. hardening
4. none of the above

12. Corrosion in concrete sewer is caused by

1. DO
2. H₂S
3. Chlorine
4. Nitrogen

13. The hydraulic mean depth of a circular sewer running full is equal to

1. d/4
2. d/2
3. d/8
4. d/6