A settling chamber can remove 100 um and 75 um sized particles (specific gravity of particles-2). It has 10 trays which are spaced 1 m apart. Chamber is 4 m in length and 1 m in width. Air (viscosity-0.00018 poise and density-1.2 kg/m) is flowing through this settling chamber at 30000 cfm (cubic foot per minute). Standard conditions prevail inside the chamber. Assuming gravitational constant as 9.8 m/s and density of water as 1000 kg/m at STP, (1) Calculate the residence time (in seconds), distance settled (in metre) and collection efficiencies (in whole numbers) for the two sizes. (ii) Are larger particles settled in this chamber? (iii) How is efficiency varying with particle size in this chamber?