Question 11. For the prediction of future population of a city, the factor to be considered, is

Question 12. The factor affecting per capita demand, is

Question 13. By boiling water, hardness can be removed if it is due to

Question 14. In slow sland filters, the turbidity of raw water can be removed only up to

Question 15. When the reduced level of the water source is higher than the reduced level of the consumer's place, water is generally supplied

Question 16. To pump water from a water reservoir 3 m deep and maximum water level at 135 m, a pump is installed to lift water up to R.L. 175 m at a constant rate of 36,00,000 litres per hour. If the length of the pipe is 1506 m and f = 0.01, ignoring other minor losses and assuming the economical diameter from Lea's formula D = 1.2 √Q, the water horse power of the pump is

Question 17. The process of passing water through beds of granular materials, is called

Question 18. Pick up the correct statement from the following:

Question 19. Surcharge storage zone of a reservoir, is

Question 20. Surge tanks are used