Definition: 1 Mark
Reasoning out: 1 Mark
Explanation 1 Mark
Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality.
The turbidity of water is based upon a comparison of the amount of light passing through a given water sample with that passing through a standard sample. Usually this is defined in terms of the depth of water to which a candle flame can be clearly distinguished.
Turbidity is caused by particles suspended or dissolved in water that scatter light making the water appear cloudy or murky. Particulate matter can include sediment - especially clay and silt, fine organic and inorganic matter, soluble colored organic compounds, algae, and other microscopic organisms.