MCQOPTIONS
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MCQOPTIONS
This section includes 31 Mcqs, each offering curated multiple-choice questions to sharpen your Environmental Science knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
What will be the surface area of the basin for a flow of 2*106 litre per day having a surface loading rate 10,000 litre/day/m2? |
| A. | 100 |
| B. | 200 |
| C. | 300 |
| D. | 400 |
| Answer» C. 300 | |
| 2. |
In which device, the primary mixing is followed by a secondary reaction zone resulting in formation of sludge blanket? |
| A. | Centrifugal pump |
| B. | Flocculator |
| C. | Tube settler |
| D. | Solid contact clarifier |
| Answer» E. | |
| 3. |
Ferric chloride is effective over a pH range of |
| A. | 3.5-6 |
| B. | 6.5-8 |
| C. | 3.5-6.5 |
| D. | 2-5 |
| Answer» D. 2-5 | |
| 4. |
1cm per second settling velocity corresponds to a surface loading of ______ litre per day per m2 |
| A. | 36000 |
| B. | 864000 |
| C. | 24000 |
| D. | 6000 |
| Answer» C. 24000 | |
| 5. |
What is the settling velocity of the particle if its diameter is 2 * 10-3cm. Given G=2.65, viscosity v=8 * 10-3cm2/Sec? |
| A. | 0.01cm/Sec |
| B. | 0.13cm/Sec |
| C. | 0.24cm/Sec |
| D. | 0.36cm/Sec |
| Answer» C. 0.24cm/Sec | |
| 6. |
Range of Displacement efficiency in the plain sedimentation tank is |
| A. | 0.25-0.5 |
| B. | 0.1-0.2 |
| C. | 0.5-0.8 |
| D. | 0.3-0.6 |
| Answer» B. 0.1-0.2 | |
| 7. |
The pulsator clarifier is a type of |
| A. | Horizontal flow sludge tank |
| B. | Vertical flow sludge tank |
| C. | Circular sludge tank |
| D. | Plain sedimentation tank |
| Answer» C. Circular sludge tank | |
| 8. |
Which of the following represents the correct relation between displacement velocity and diameter of the particle? |
| A. | v1 = (8Bg (G-1) d/f) 1/2 |
| B. | v1 = (8Bg (G-1) d2/f)2 |
| C. | v1 = (8Bg (G-1) d/f) |
| D. | v1 = (8Bg (G-1) d/f)2 |
| Answer» B. v1 = (8Bg (G-1) d2/f)2 | |
| 9. |
Which device solved the problem of unstable hydraulic conditions and operation of sludge removal equipment? |
| A. | Centrifugal pump |
| B. | Pulsator clarifier |
| C. | Tube settler |
| D. | Flocculator |
| Answer» D. Flocculator | |
| 10. |
Which of the following statement is wrong regarding Iron salt? |
| A. | Iron salt produces less floc than Alum |
| B. | Detention time for sedimentation by using Iron salt as coagulant is less |
| C. | Handling of Iron salt requires some skills |
| D. | Iron removes H2S, taste and odor |
| Answer» B. Detention time for sedimentation by using Iron salt as coagulant is less | |
| 11. |
Why Magnesium carbonate is not commonly preferred as coagulant? |
| A. | It is expensive |
| B. | It does not remove color |
| C. | Formation of sludge |
| D. | The time required for floc formation is less |
| Answer» D. The time required for floc formation is less | |
| 12. |
The detention period of the vertical flow clarifier is |
| A. | 1-1.5 |
| B. | 2 |
| C. | 3.5 |
| D. | 4 |
| Answer» B. 2 | |
| 13. |
State whether the following statement is true or false.The sedimentation basin should be made as deep as possible. |
| A. | True |
| B. | False |
| Answer» C. | |
| 14. |
In a fill and draw type sedimentation tank, a detention period of ____ hours is provided. |
| A. | 6 |
| B. | 12 |
| C. | 18 |
| D. | 24 |
| Answer» E. | |
| 15. |
The detention period of a rectangular tank is given by |
| A. | t0= LBH/Q |
| B. | t0= LB/HQ |
| C. | t0= Q/LBH |
| D. | t0= HQ/LB |
| Answer» B. t0= LB/HQ | |
| 16. |
In which type of sedimentation, flocculent suspension of high concentration takes place? |
| A. | Type I sedimentation |
| B. | Type II sedimentation |
| C. | Type III sedimentation |
| D. | Type IV sedimentation |
| Answer» E. | |
| 17. |
In which type of tube settler, tubes are slightly inclined in the direction of normal flow? |
| A. | Solid contact clarifier |
| B. | Steeply inclined tube settler |
| C. | Vertical tube settler |
| D. | Horizontal tube settler |
| Answer» E. | |
| 18. |
The chemical composition of Chlorinated Copperas is |
| A. | Fe2 (SO4)3 + FeCl3 |
| B. | FeSO4.9H2O |
| C. | FeSO4.18H2O |
| D. | Fe2 (SO4)3 |
| Answer» B. FeSO4.9H2O | |
| 19. |
Settling velocity of a spherical body in a viscous fluid is given by |
| A. | Reynolds law |
| B. | Newton's law |
| C. | Stokes law |
| D. | Charles law |
| Answer» D. Charles law | |
| 20. |
The design value of surface loading for horizontal flow circular sedimentation is |
| A. | 30-40m3/m2/d |
| B. | 20-30m3/m2/d |
| C. | 10-20m3/m2/d |
| D. | 50-100m3/m2/d |
| Answer» B. 20-30m3/m2/d | |
| 21. |
The detention period of a flash mixer is |
| A. | 2 minutes |
| B. | 30 minutes |
| C. | 1 hour |
| D. | 2 hours |
| Answer» B. 30 minutes | |
| 22. |
'C' in the following figure represents the ________ |
| A. | Impeller |
| B. | Impeller shaft |
| C. | Deflecting wall |
| D. | Flash mixer wall |
| Answer» D. Flash mixer wall | |
| 23. |
In which type of sedimentation,the flocculent suspension of high concentration takes place? |
| A. | Type I sedimentation |
| B. | Type II sedimentation |
| C. | Type III sedimentation |
| D. | Type IV sedimentation |
| Answer» E. | |
| 24. |
Which of the following is correctly paired? |
| A. | C – Impeller |
| B. | D – Outlet |
| C. | F – Deflecting wall |
| D. | E – Impeller |
| Answer» E. | |
| 25. |
Detention time for a circular tank is given by |
| A. | t =D (D + 0.785H) /Q |
| B. | t = D (0.1D + 0.785H) /Q |
| C. | t = D2 (0.01D + 0.785H) |
| D. | t = D2 (0.01D + 0.785H) /Q |
| Answer» E. | |
| 26. |
Settling tank efficiency is reduced by1. Eddy current2. Surface current3. Density current |
| A. | 1, 2 |
| B. | 1, 2, 3 |
| C. | 2, 3 |
| D. | 1, 3 |
| Answer» C. 2, 3 | |
| 27. |
The speed of impeller in a flash mixer is |
| A. | 45rpm |
| B. | 60rpm |
| C. | 110rpm |
| D. | 200rpm |
| Answer» D. 200rpm | |
| 28. |
In the expression vS = 1.8 (g*d (G-1)) 1/2, the diameter of spherical particle is |
| A. | 0.1mm |
| B. | < 0.1mm |
| C. | 1mm |
| D. | >1mm |
| Answer» E. | |
| 29. |
What is the settling velocity of the particle in the wastewater if its diameter is 2 * 10-3cm. Given G=2.65, viscosity v=8 * 10-3cm2/Sec? |
| A. | 0.01cm/Sec |
| B. | 0.13cm/Sec |
| C. | 0.24cm/Sec |
| D. | 0.36cm/Sec |
| Answer» C. 0.24cm/Sec | |
| 30. |
Which of the following represents the impeller shaft? |
| A. | F |
| B. | E |
| C. | C |
| D. | B |
| Answer» B. E | |
| 31. |
The overflow rate for a plain sedimentation tank is ______ litre/day/metre2. |
| A. | 50000 |
| B. | 40000 |
| C. | 12000 |
| D. | 30000 |
| Answer» D. 30000 | |