Horrock's appar is used for-
Ans. is 'b' i.e., Chlorine demand InstrumentUtilityHorrocks ApparatusChlorinator/ ChloronomeChloroscopeChlorine demand estimationMixing or regulating dose of chlorineMeasuring residual level of chlorine
Wind velocity
Chlorine demand
Water contamination
Coliform count
Environment and Health