SSC JE Exam - first law of thermodynamics non flow and flow energy equations enthalpy steady flow energy equation One Line Questions & Answers

1. For a simple compressible substance undergoing a non-flow process, the first law is Q = ΔU + W. If the process is reversible and involves only boundary work, then W is given by: — ∫PdV

2. If a system absorbs 50 kJ of heat and its internal energy increases by 30 kJ, the work done by the system is: — 20 kJ

3. If a system undergoes a process where Q = 100 kJ and W = 40 kJ, what is the change in internal energy (ΔU)? — 60 kJ

4. For a non-flow process, if W = -50 kJ (work is done on the system) and Q = 20 kJ, what is ΔU? — 30 kJ

5. In a boiler operating under steady flow, heat is typically: — Added to the system

6. What is the primary application of the Steady Flow Energy Equation? — Analyzing thermodynamic devices like turbines, pumps, and boilers

7. The SFEE is typically expressed in terms of rates (per unit time) for: — Open systems

8. The first law of thermodynamics is a statement of which conservation principle? — Conservation of Energy

9. Enthalpy (H = U + PV) is a property that is particularly useful for analyzing processes involving: — Constant pressure heat transfer

10. The first law of thermodynamics is a consequence of the principle of: — Energy conservation

11. In a cyclic process, the net change in internal energy of the system is: — Zero

12. The Steady Flow Energy Equation (SFEE) is derived based on which fundamental principle? — First Law of Thermodynamics

13. What is enthalpy (H) defined as? — H = U + PV

14. For a steady flow system with one inlet and one outlet, the SFEE can be written as: — h1 + V1^2/2 + gZ1 + Q = h2 + V2^2/2 + gZ2 + W

15. For a steady flow adiabatic process with no work interaction, the SFEE reduces to: — h1 + V1^2/2 + gZ1 = h2 + V2^2/2 + gZ2

16. In the SFEE, if kinetic and potential energy changes are negligible, and the process is adiabatic (q=0), what does the equation become? — h1 + w = h2

17. For a steady flow device with negligible heat transfer and negligible changes in kinetic and potential energy, the SFEE reduces to: — w = h2 - h1

18. For a non-flow process, the change in internal energy of a system is equal to: — Heat added minus work done

19. In the first law equation Q = ΔU + W, what does W represent? — Work done by the system

20. Which of the following is NOT a form of energy transfer considered in the SFEE? — Mass transfer

21. In the context of the first law for non-flow processes, if a system releases heat (Q is negative) and does work (W is positive), the internal energy will: — Decrease

22. Which of the following is NOT an energy term typically considered in the Steady Flow Energy Equation? — Chemical Energy

23. For a constant pressure process, the heat transfer is equal to the change in: — Enthalpy

24. What is the term 'flow work' or 'flow energy' fundamentally related to? — The work required to push the fluid across the control volume boundary

25. The SFEE accounts for the energy transfer due to: — Internal energy, flow work, kinetic energy, potential energy, heat, and work

26. What is the unit of enthalpy? — J/kg

27. The term gZ in the SFEE represents the change in: — Potential energy

28. Which of the following is an intensive property? — Temperature

29. The SFEE is applicable to systems where: — Mass crosses the boundary

30. In the SFEE equation (h1 + V1^2/2 + gZ1 + q = h2 + V2^2/2 + gZ2 + w), what does 'q' represent? — Heat transfer per unit mass

31. The flow energy equation is essentially an application of the first law of thermodynamics to: — Open systems

32. For a pump operating under steady flow, the work input is typically: — Positive

33. For a steady flow process through a heat exchanger, what is the typical work transfer (w)? — Zero

34. In a turbine operating under steady flow, the work output is typically: — Positive

35. In the definition of enthalpy H = U + PV, what do U, P, and V represent respectively? — Internal Energy, Pressure, Volume

36. Which of the following is a key assumption for the Steady Flow Energy Equation? — Mass flow rate is constant

37. The flow work or flow energy term in the SFEE is represented by: — PV

38. For a system undergoing an adiabatic process, which of the following is true according to the first law of thermodynamics (non-flow)? — Q = 0, so ΔU = W

39. For a steady flow process with negligible changes in kinetic and potential energy, the SFEE simplifies to: — Δh = q + w

40. Which of the following represents the first law of thermodynamics for a non-flow process? —

41. The term 'steady flow' implies that: — The properties at any point in the control volume do not change with time

42. If a system is heated and does no work, the change in its internal energy is equal to: — The heat supplied

43. Consider a control volume where fluid enters at state 1 and leaves at state 2. For steady flow, the SFEE states that the net rate of energy transfer by heat and work is equal to: — The net rate of energy carried by mass

44. For a steady flow process, the rate of energy entering the control volume is equal to: — The rate of energy leaving the control volume

45. For a steady flow system, the total energy entering the control volume per unit time is equal to: — Total energy leaving the control volume per unit time

46. Which term in the enthalpy definition (H = U + PV) accounts for the energy associated with the system's boundaries? — PV

47. Consider a throttling process (e.g., in a valve). What is the change in enthalpy for an ideal throttling process? — Zero

48. Which of the following statements is TRUE for a system undergoing an isothermal process (constant temperature) where heat is added? — ΔU = 0, so Q = W

49. The first law of thermodynamics for a cyclic process can be stated as: — ΣQ = ΣW

first law of thermodynamics non flow and flow energy equations enthalpy steady flow energy equation - One Line Questions