Thermodynamics Mechanical previous year questions with answer

Ques 41 GATE 2016 SET-2

The internal energy of an ideal gas is a function of

Ques 42 GATE 2016 SET-2

The heat removal rate from a refrigerated space and the power input to the compressor are 7.2 kW and 1.8 kW, respectively. The coefficient of performance (COP) of the refrigerator is ________.

Ques 43 GATE 2016 SET-2

Consider a simple gas turbine (Brayton) cycle and a gas turbine cycle with perfect regeneration. In both the cycles, the pressure ratio is 6 and the ratio of the specific heats of the working medium is 1.4. The ratio of minimum to maximum temperatures is 0.3 (with temperatures expressed in K) in the regenerative cycle. The ratio of the thermal efficiency of the simple cycle to that of the regenerative cycle is ________.

Ques 44 GATE 2016 SET-2

A piston-cylinder device initially contains 0.4 m³ of air (to be treated as an ideal gas) at 100 kPa and 80°C. The air is now isothermally compressed to 0.1 m³. The work done during this process is ________ kJ. (Take the sign convention such that work done on the system is negative)

Ques 45 GATE 2016 SET-2

A reversible cycle receives 40 kJ of heat from one heat source at a temperature of 127°C and 37 kJ from another heat source at 97°C. The heat rejected (in kJ) to the heat sink at 47°C is ________.

Ques 46 GATE 2016 SET-2

A refrigerator uses R-134a as its refrigerant and operates on an ideal vapour-compression refrigeration cycle between 0.14 MPa and 0.8 MPa. If the mass flow rate of the refrigerant is 0.05 kg/s, the rate of heat rejection to the environment is ________ kW. Given data: At P=0.14 MPa, h=236.04 kJ/kg, s=0.9322 kJ/kg-K (saturated vapour). At P=0.8 MPa, h=272.05 kJ/kg, s=0.9322 kJ/kg-K (superheated vapour). At P=0.8 MPa, h=93.42 kJ/kg (saturated liquid).

Ques 47 GATE 2016 SET-2

The partial pressure of water vapour in a moist air sample of relative humidity 70% is 1.6 kPa, the total pressure being 101.325 kPa. Moist air may be treated as an ideal gas mixture of water vapour and dry air. The relation between saturation temperature (T_s in K) and saturation pressure (p_s in kPa) for water is given by ln(p_s/p_o) = 14.317 - 5304/T_s, where p_o = 101.325 kPa. The dry bulb temperature of the moist air sample (in °C) is ________.

Ques 48 GATE 2016 SET-1

Which of the following statements are TRUE with respect to heat and work?
(i) They are boundary phenomena
(ii) They are exact differentials
(iii) They are path functions

Ques 49 GATE 2016 SET-1

Propane (C₃H₈) is burned in an oxygen atmosphere with 10% deficit oxygen with respect to the stoichiometric requirement. Assuming no hydrocarbons in the products, the volume percentage of CO in the products is ________.

Ques 50 GATE 2016 SET-1

The INCORRECT statement about regeneration in vapor power cycle is that