One kg of air in a closed system undergoes an irreversible process from an initial state of p1 = 1 bar (absolute) and T1 = 27°C, to a final state of p2 = 3 bar (absolute) and T2 = 127°C. If the gas constant of air is 287 J/kg.K and the ratio of the specific heats γ = 1.4, then the change in the specific entropy (in J/kg.K) of the air in the process is

Indeterminate, as the process is irreversible

One kg of air in a closed system undergoes an irreversible process fro

1.	One kg of air in a closed system undergoes an irreversible process from an initial state of p1 = 1 bar (absolute) and T1 = 27°C, to a final state of p2 = 3 bar (absolute) and T2 = 127°C. If the gas constant of air is 287 J/kg.K and the ratio of the specific heats γ = 1.4, then the change in the specific entropy (in J/kg.K) of the air in the process is
A.	-26.3
B.	28.4
C.	172
D.	Indeterminate, as the process is irreversible
Answer» B. 28.4

Discussion

No Comment Found

Related MCQs

A car engine operates with a thermal efficiency of 35%. Assume the air-conditioner has a coefficient of performance of 3 working as a refrigerator cooling the inside using engine shaft work to drive it. How much fuel energy should be spend extra to remove 1 kJ from the inside?
In a cryogenic experiment you need to keep a container at -125°C although it gains 100 W due to heat transfer. What is the smallest motor you would need for a heat pump absorbing heat from the container and rejecting heat to the room at 20°C?
A cyclic machine, as shown below, receives 325 kJ from a 1000 K energy reservoir. It rejects 125 kJ to a 400 K energy reservoir and the cycle produces 200kJ of work as output. Is this cycle reversible, irreversible, or impossible?
An air-conditioner provides 1 kg/s of air at 15°C cooled from outside atmospheric air at 35°C. Estimate the amount of power needed to operate the air-conditioner.
A heat pump is used to meet the heating requirements of a house and maintain it at 20°C. On a day when the outdoor air temperature drops to 2°C, the house is estimated to lose heat at a rate of 80,000 kJ/h. If the heat pump under these conditions has a COP of 2.5, determine the rate at which heat is absorbed from the cold outdoor air.
A heat pump is used to meet the heating requirements of a house and maintain it at 20°C. On a day when the outdoor air temperature drops to 2°C, the house is estimated to lose heat at a rate of 80,000 kJ/h. If the heat pump under these conditions has a COP of 2.5, determine the power consumed by the heat pump.
The food compartment of a refrigerator is maintained at 4°C by removing heat from it at a rate of 360 kJ/min. If the required power input to the refrigerator is 2kW, determine the rate of heat rejection to the room that houses the refrigerator.
The food compartment of a refrigerator is maintained at 4°C by removing heat from it at a rate of 360 kJ/min. If the required power input to the refrigerator is 2kW, determine the coefficient of performance of the refrigerator.
A car engine with a power output of 50 kW has a thermal efficiency of 24 percent. Determine the fuel consumption rate of this car if the fuel has a heating value of 44,000 kJ/kg .
Heat is transferred to a heat engine from a furnace at a rate of 80 MW. If the rate of waste heat rejection to a nearby river is 50 MW, determine the thermal efficiency for this heat engine.

Discussion

No Comment Found

Related MCQs

Reply to Comment