22. The collection efficiency by impaction increases with
A.increasing particle diameter
B.increasing air flow velocity
C.both (a) and (b)
D.increasing particle size
23. The efficiency of fibrous filter by combined mechanism is given by(where ηimp,ηint,ηdif are the efficiencies by impaction, interception and diffusion respectively)
A.1 - ηimpηintηdif
B.1 - (1 - ηimp)(1 - ηint)( 1 - ηdif)
C.1 - ( ηimpηint/ηdif)
D.None of the above
24. The heat conduction in dry air is
A.less rapid than in steam
B.more rapid than in steam
C.similar to steam
D.none of these
25. For laminar flow of Newtonian fluid through a smooth round pipe, the ratio of average fluid velocity to the maximum velocity is
A.0.5
B.0.75
C.0.87
D.0.37
26. The reduction of number of cells from 1010 to one will result into the del factor (Δ) of
A.1
B.10
C.23
D.103
27. Sterilization can be carried out by
A.heat
B.radiation
C.chemical agents
D.all of these
28. The collection efficiency by the inertial impaction mechanism is the function of
A.Stokes and Reynolds number
B.Stokes and Schmidt number
C.Grashoff and Reynolds number
D.Stokes and Grashof number
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