253. In SI units the power of sound is represented in
A. kgs
B. joules
C. neutons
D. watts.

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254. Assertion : The minimum self cleansing velocity in the sewer, at least once a day, must be generated. Reason : 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.

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255. Assertion : The determination of pH value of sewerage is important. Reason : The efficiency of certain treatment methods depends upon the availability of pH value. Codes :
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.

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256.  Assertion : Discharging the effluents from the oxidation ponds just up stream of lakes or reservoirs is undesirable. Reason : The discharged algae get settled in the reservoirs and cause anaerobic decomposition and other water qualities. Codes :
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.

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257. Assertion : A free board of 0.3 m is provided above the top sewage line in septic tanks. Reason : It helps to accommodate the scum in the septic tank. Codes :
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.

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258. The liquid wastes from kitchens, bath rooms and wash basins, is not called
A. liquid waste
B. sullage
C. sewage
D. none of these.

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259.  Dry weather flow is :
A. average daily rate of flow
B. average monthly rate of flow
C. average annual rate of flow
D. water supply allowance per capita

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