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The ratio of oxygen available to the oxygen required for stabilisation of sewage is called the __________________? A. Bacterial stability factorB. Relative stability C. Biological oxygen demand (BOD) D. Oxygen ion concentration
In troposphere (the weather domain), the temperature ‘t’ at height ‘h’ above the spa level in metres is given by (where, temperature at sea level is 15°C and t is in °C ? A. t = 15 – 0.0065h B. t = 15 + 0.0065h C. t = 0.0035h -15 D. t = 15 –…
Which of the following is the most severe air pollutant ? A. HydrocarbonsB. NOx C. SO2 D. CO
Dust collection efficiency of a cyclone separator depends upon its______________? A. Diameter B. Inlet gas velocity C. Overall heightD. All A., B. & C.
The major reason of hydrodynamic noise (i.e., noise resulting from liquid flow) is_________________? A. Pipe vibrationsB. Cavitation C. Boundary layer separation D. Fluctuation in liquid flow
Noise produced by cooling fans (employed in air cooled heat exchangers or cooling tower) is mainly caused due to the turbulence created by blade passage through air. It can be reduced by use of a slower fan_________________? A. With greater number of blades B. Of increased diameterC. Both A. & B. D. Neither A. nor…
Main pollutants released from iron & steel industry is__________________? A. CO, CO2 & SO2 B. H2S, NO & SO3 C. CO2, H2S & NO2 D. SO3, NO2 & CO2
A shallow pond in which the sewage is retained and biologically treated is called__________________? A. Oxidation B. Imhoff tank C. Lagoon D. Skimming tank
Suspended solid present in the waste water generated in blast furnace gas cooling and cleaning plant is removed by__________________? A. Biological oxygen pondB. Radial settling tank (thickener) using coagulant (lime & ferrous sulphate) C. Lagoons D. Filtration
Inhalation of silica dust causes a disease called__________________? A. BronchitisB. Silicosis C. Pneumoconiosis D. None of these