16. The fluid property that remains unchanged across a normal shock wave-
A. Static pressure
B. Mass density
C. Stagnation pressure
D. Stagnation enthalpy
17. In a reaction turbine stage enthalpy drop in the stator blades is 4.62 kJ/kg and that in the rotor blades is 2.38 kJ/kg. The degree of reaction of the stage is-
A. 0.34
B. 0.55
C. 0.53
D. 0.45
18. In rocket propulsion, the oxygen for combustion of its fuel is taken from-
A. Surrounding air
B. Surrounding air and compressed atmosphere air
C. The rocket itself
D. Compressed atmospheric pressure
19. Increasing the number of reheating stages in a gas turbine to infinity makes the expansion tending-
A. Isothermal
B. Isobaric
C. Adiabatic
D. Reversible Adiabatic
20. In a gas turbine cycle, the turbine output is 600 kJ/kg, the compressor work is 400 kJ/kg and the heat supplied is 1000 kJ/kg. Find the thermal efficiency-
A. 20%
B. 40%
C. 65%
D. 80%