Practice Pakistan's most useful MCQs for competitive exams

In SI units the power of sound is represented in __________________?

• (A)  Kgs
• (B)  Joules
• (C)  Newtons
• (D)  Watts

Answer

Submitted By :Ali Uppal

For the survival of fish in a river stream, the minimum dissolved oxygen is prescribed________________?

• (A)  3 ppm
• (B)  4 ppm
• (C)  5 ppm
• (D)  10 ppm

Answer

Submitted By :Ali Uppal

The coagulant widely used for sewage treatment, is_________________?

• (A)  Alum
• (B)  Ferric chloride
• (C)  Ferric sulphate
• (D)  Chlorinated copperas

Answer

Submitted By :Ali Uppal

In a sludge digestion tank if the moisture content of sludge V1 litres is reduced from p1 % to p2 % the volume V2 is____________________?

• (A)  [(100 + P1)/(100 – P2)] V1
• (B)  [(100 – P1)/(100 + P2)] V1
• (C)  [(100 – P1)/(100 – P2)] V1
• (D)  [(100 + P2)/(100 – P1)] V1

Answer

Submitted By :Ali Uppal

The sewage treatment in septic tanks is due to__________________?

• (A)  Anaerobic decomposition
• (B)  Aerobic decomposition
• (C)  Parasitic decomposition
• (D)  None of these

Answer

Submitted By :Ali Uppal

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

Answer

Submitted By :Ali Uppal

3.0 ml of raw sewage is diluted to 300 ml. The D.O. concentration of the diluted sample at the beginning of the test was 8 mg/l. After 5 day-incubation at 20°C, the D.O. concentration was 5 mg/l. The BOD of raw sewerage is______________________?

• (A)  100 mg/l
• (B)  200 mg/l
• (C)  300 mg/l
• (D)  400 mg/l

Answer

Submitted By :Ali Uppal

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?

• (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

Answer

Submitted By :Ali Uppal

Dry water flow in a combined sewer, is______________________?

• (A)  Industrial sewage
• (B)  Domestic sewage
• (C)  Storm water
• (D)  Inclusive of domestic and industrial sewage but excludes storm water

Answer

Submitted By :Ali Uppal

In sewage having fully oxidised organic matter, the nitrogen exists in the form of________________?

• (A)  Nitrites
• (B)  Nitrates
• (C)  Free ammonia
• (D)  Aluminoid nitrogen

Answer

Submitted By :Ali Uppal