Q.1
Superheated R-at 0.5 MPa, 20°C is cooled in a piston-cylinder at constant temperature to a final two-phase state with quality of 50%. The refrigerant mass is 5 kg, and during the processkJ of heat is removed. Find the necessary work.
  • a) -67.9 kJ
  • b) -77.9 kJ
  • c) -87.9 kJ
  • d) -97.9 kJ
Q.2
Air atK flows with 3 kg/s into a heat exchanger and out at 100°C. How much (kg/s) water coming in atkPa, 20°C can the air heat to the boiling point?
  • a) 0.37 kg/s
  • b) 0.17 kg/s
  • c) 0.27 kg/s
  • d) 0.57 kg/s
Q.3
Nitrogen gas flows into a convergent nozzle atkPa,K and very low velocity. It flows out of the nozzle atkPa,K. If the nozzle is insulated find the exit velocity.
  • a) 681.94 m/s
  • b) 581.94 m/s
  • c) 481.94 m/s
  • d) none of the mentioned
Q.4
A steam turbine has an inlet of 2 kg/s water atkPa, 350°C and velocity ofm/s. The exit is atkPa, x = 1 and very low velocity. Find the specific work.
  • a) 382.3 kJ/kg
  • b) 482.3 kJ/kg
  • c) 582.3 kJ/kg
  • d) 682.3 kJ/kg
Q.5
A steam turbine has an inlet of 2 kg/s water atkPa, 350°C and velocity ofm/s. The exit is atkPa, x = 1 and very low velocity. Find the power produced.
  • a) 664.6 kW
  • b) 764.6 kW
  • c) 864.6 kW
  • d) 964.6 kW
Q.6
10kg of water in a piston-cylinder exists as saturated liquid/vapour atkPa, with a quality of 50%. It is now heated till the volume triples. The mass of piston is such that a cylinder pressure ofkPa will float it. Find the heat transfer in the process.
  • a) 23961 kJ
  • b) 24961 kJ
  • c) 25961 kJ
  • d) 26961 kJ
Q.7
A vertical cylinder fitted with a piston contains 5 kg of R-at 10°C. Heat is transferred causing the piston to rise until the volume has doubled. Additional heat is transferred until the temperature inside reaches 50°C, at which point the pressure inside the cylinder is 1.3 MPa. Find the work done.
  • a) 34.1 kJ
  • b) 44.1 kJ
  • c) 54.1 kJ
  • d) 64.1 kJ
Q.8
Arigid tank contains methane atkPa,K. It is now cooled down to 300K. Find the heat transfer.
  • a) –402.4 kJ
  • b) –502.4 kJ
  • c) –602.4 kJ
  • d) –702.4 kJ
Q.9
A rigid container has 2kg of carbon dioxide gas atK,kPa that is heated toK. Find the heat transfer using heat capacity.
  • a) 231.2 kJ
  • b) 241.2 kJ
  • c) 251.2 kJ
  • d) 261.2 kJ
Q.10
A piston cylinder contains 3kg of air at 20°C andkPa. It is now heated up in a constant pressure process toK. Find the heat transfer.
  • a) 941 kJ
  • b) 951 kJ
  • c) 961 kJ
  • d) 971 kJ
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