Dissolved oxygen content in river water is around _____________ ppm?
Dissolved oxygen content in river water is around _____________ ppm? A. 5 B. 100 C. 250 D. 500
Dissolved oxygen content in river water is around _____________ ppm? A. 5 B. 100 C. 250 D. 500
Maximum allowable concentration of CO2 in air for safe working is _____________ ppm (parts per million)? A. 50 B. 1000 C. 2000D. 5000
____________ substances present in sewage are removed in grit chamber during sewage treatment? A. Organic B. FattyC. Inorganic D. Dissolved
Industrial workers working in leather tanning & manufacturing units are prone to suffer from ___________________? A. Respiratory ailments (e.g. bronchitis)B. Skin diseases (e.g. dermatitis) C. Silicosis D. Blurred vision
Ionisation potential employed in the industrial electrostatic precipitator is of the order of_______________? A. 30 to 70 kV DC B. 30 to 70 kV AC C. 230 V AC D. 230 V DC
Noise level during normal conversation among men is about ______________ decibels? A. 10B. 45 C. 90 D. 115
Exposure to small amount of ______________ results in high blood pressure & heart disease in human beings? A. Hydrogen sulphide B. MercuryC. Cadmium D. Asbestos
Which of the following acts as a natural source of air pollution ? A. Forest fire B. DeforestationC. Volcanic eruption D. None of these
Moist atmospheric air at high temperature (e.g., in summer) having high concentration of sulphur dioxide causes________________? A. Fading of dyes on textiles B. Corrosion, tarnishing & soiling of metals C. Reduced strength of textilesD. All A., B. and C.
Tri-sodium phosphate is used in boiler water treatment to reduce____________________? A. TurbidityB. Caustic embrittlement C. Suspended silica D. Dissolved oxygen