Pressure-enthalpy chart is useful in refrigeration. The change in internal energy of an ideal fluid used in ideal refrigeration cycle is_____________________?

Related Mcqs:

1. In an ideal refrigeration cycle, the change in internal energy of the fluid is_____________?

   A. +ve
   B. -ve
   C. 0
   D. Either of the above three; depends on the nature of refrigerant

2. Enthalpy of formation of NH3 is – 46 kJ/kg mole. The enthalpy change for the gaseous reaction, 2NH3 → N2 + 3H2, is equal to _____________ kJ/kg. mole?

   A. 46
   B. 92
   C. -23
   D. -92

3. A refrigeration cycle is a reversed heat engine. Which of the following has the maximum value of the co-efficient of performance (COP) for a given refrigeration effect ?

   A. Vapor compression cycle using expansion valve
   B. Air refrigeration cycle
   C. Vapor compression cycle using expansion engine
   D. Carnot refrigeration cycle

4. A car tyre of volume 0.057 m3 is inflated to 300 kPa at 300 K. After the car is driven for 10 hours, the pressure in the tyre increases to 330 kPa. Assume air is an ideal gas and Cv for air is 21 J/mole.K. The change in the internal energy of air in the tyre in J/mole is__________________?

   A. 380
   B. 630
   C. 760
   D. 880

5. High pressure steam is expanded adiabatically and reversibly through a well insulated turbine, which produces some shaft work. If the enthalpy change and entropy change across the turbine are represented by ΔH and ΔS respectively for this process ?

   A. Δ H = 0 and ΔS = 0
   B. Δ H ≠ 0 and ΔS = 0
   C. Δ H ≠ 0 and ΔS ≠ 0
   D. Δ H = 0 and ΔS ≠ 0

6. Ideal refrigeration cycle is____________________?

   A. Same as Carnot cycle
   B. Same as reverse Carnot cycle
   C. Dependent on the refrigerant’s properties
   D. The least efficient of all refrigeration processes

7. The internal energy of an ideal gas does not change in a reversible _____________ process?

   A. Isothermal
   B. Adiabatic
   C. Isobaric
   D. Isometric

8. A refrigeration cycle is the same as a _____________ cycle?

   A. Turbine
   B. Heat engine
   C. Reversed heat engine
   D. None of these

9. Internal energy change of a system over one complete cycle in a cyclic process is__________________?

   A. Zero
   B. +ve
   C. -ve
   D. Dependent on the path

10. The partial molar enthalpy of a component in an ideal binary gas mixture of composition Z, at a temperature T and pressure P, is a function only of________________?

    A. T
    B. T and P
    C. T, P and Z
    D. T and Z