In an experiment to determine dryness fraction of steam, the mass of water separated was 1.2 kg in 15 mts. and the mass of steam passed out in same time was 4.8 kg. Dryness fraction is
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One kg of steam sample contains 0.8 kg dry steam? Its dryness fraction is
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Hard coke is produced by carburization of coal at
A. Atmospheric temperature
B. 500-600°C
C. 700-850°C
D. 950-1100°C
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When the back pressure of a nozzle is below the designed value of pressure at exit of nozzle, the nozzle is said to be
A. Choked
B. Under-damping
C. Over-damping
D. None of these
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When the nozzle operates with the maximum mass flow, the nozzle is said to be
A. Choked
B. Under-damping
C. Over-damping
D. None of these
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The maximum discharge of steam through a convergent-divergent nozzle depends upon
A. Area of nozzle at throat
B. Initial pressure and volume of steam
C. Final pressure of steam leaving the nozzle
D. Both (A) and (B)
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The variation of steam pressure in the nozzle depends upon
A. Velocity of steam
B. Specific volume of steam
C. Dryness fraction of steam
D. All of these
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The efficiency of an impulse turbine is maximum when (where Vb = Blade speed, V = Absolute velocity of steam entering the blade and α = Nozzle angle)
A. Vb = 0.5 V cosα
B. Vb = V cosα
C. Vb = 0.5 V2 cosα
D. Vb = V2 cosα
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The maximum efficiency of a De-Laval turbine is (where α = Nozzle angle)
A. sin2 α
B. cos2 α
C. tan2 α
D. cot2 α
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