Determination of Turbidity in Water

The good quality of water should have dissolved solids of?
When the sewage becomes stronger, the Turbidity of waste water
Light source - Tungsten filament lamp operated at a colour temperature between?
The Formazin Suspension is defined as ___________ Nephelometric Turbidity Units (NTU).
Water sample has a Turbidity value of 8 JTU. What is your comment on this?