Which of the following instruments is used to determine the turbidity of water?

The instrument used to determine the turbidity of water is a Secchi disc. Turbidity refers to the cloudiness or haziness of a liquid, caused by the presence of suspended particles in the water. The Secchi disc is a simple, circular device that is used to measure water turbidity by determining the depth at which the disc is no longer visible when it is lowered into the water. The Secchi disc is typically painted in alternating black and white quadrants, and is used by lowering it into the water until it is no longer visible. The depth at which the disc disappears is recorded, and this measurement is used to estimate the turbidity of the water. Therefore, the instrument used to determine the turbidity of water is a Secchi disc.