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

Question: The maximum depth of sedimentation tanks is limited to________________?

• 1. 2 m
• 2. 3 m
• 3. 4 m
• 4. 6 m

Question: Corrosion of well pipes may not be reduced by_________________?

• 1. reducing the draw down and the pumping rate
• 2. reducing the flow velocity
• 3. using thicker pipes
• 4. using screens having larger area of openings

Question: Acidity in water is caused due to_______________?

• 1. Mineral acids
• 2. Free CO2
• 3. Iron sulphate
• 4. All the above