Question: Biochemical Oxygen Demand (B.O.D.) of safe drinking water must be________________?

• 1. nil
• 2. 5
• 3. 10
• 4. 15

Question: In distribution pipes, drain valves are provided at_______________?

• 1. lower point
• 2. higher point
• 3. junction points
• 4. any where

Question: Asbestos pipes are ______________?

• 1. light in weight and easy to transport
• 2. highly resistant to corrosion
• 3. high flexible to accommodate deflection upto 12°
• 4. all the above

Question: By boiling water, hardness can be removed if it is due to_________________?

• 1. calcium sulphate
• 2. magnesium sulphate
• 3. calcium nitrate
• 4. calcium bicarbonate

Question: The least thickness of class B cast iron (spun) pipe, is_________________?

• 1. 7.2 mm
• 2. 7.9 mm
• 3. 8.6 mm
• 4. 10 mm

Question: The R.L. of ground water table on the sides of a valley is 1505 m whereas R.L. of the stream water is 1475 m. If 60° slope consists of pervious soil between R.L. 1485 m to 1500 m, the gravity spring may be expected at the point of reduced level___________

• 1. 1500 m
• 2. 1505 m
• 3. 1475 m
• 4. 1485 m

Question: According to IS : 1172-1963, a minimum of 135 litres of water capita per day, is required for________________?

• 1. Boarding schools
• 2. Nurses home and medical quarters
• 3. hostels
• 4. all the above

Question: The factor affecting per capita demand, is___________________?

• 1. size of the city
• 2. climatic conditions
• 3. pressure in water mains
• 4. all the above

Question: The specific retention is least in case of_______________?

• 1. Clay
• 2. Sand
• 3. Silt
• 4. Coarse gravel

Question: For determining the velocity of flow of underground water, the most commonly used non-empirical formula is________________?

• 1. Darcy’s formula
• 2. Slichter’s formula
• 3. Hazen’s formula
• 4. Lacy’s formula