SSC JE Exam - first law of thermodynamics non flow and flow energy equations enthalpy steady flow energy equation Online Test (MCQ Quiz)

1. The first law of thermodynamics is a statement of which conservation principle?

A) Conservation of Mass B) Conservation of Momentum C) Conservation of Energy D) Conservation of Charge

2. For a non-flow process, the change in internal energy of a system is equal to:

A) Heat added minus work done B) Work done minus heat added C) Heat added plus work done D) Heat added divided by work done

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

A) Q = ΔU + W B) W = ΔU + Q C) Q = W - ΔU D) ΔU = Q - W

4. In the first law equation Q = ΔU + W, what does W represent?

A) Heat supplied to the system B) Change in internal energy C) Work done by the system D) Work done on the system

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

A) 60 kJ B) 140 kJ C) 40 kJ D) 100 kJ

6. For a system undergoing an adiabatic process, which of the following is true according to the first law of thermodynamics (non-flow)?

A) Q = 0, so ΔU = W B) W = 0, so ΔU = Q C) ΔU = 0, so Q = W D) Q = W = 0

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

A) Equal to the net heat added B) Equal to the net work done C) Zero D) Dependent on the path

8. The first law of thermodynamics for a cyclic process can be stated as:

A) ΣQ = ΣW B) ΣQ = ΣΔU C) ΣW = ΣΔU D) ΣQ + ΣW = 0

9. What is enthalpy (H) defined as?

A) H = U - PV B) H = U + PV C) H = PV - U D) H = U / PV

10. In the definition of enthalpy H = U + PV, what do U, P, and V represent respectively?

A) Pressure, Volume, Internal Energy B) Internal Energy, Pressure, Volume C) Volume, Pressure, Internal Energy D) Internal Energy, Volume, Pressure

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

A) Internal Energy B) Enthalpy C) Entropy D) Temperature

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

A) U B) P C) V D) PV

13. For a steady flow process, the rate of energy entering the control volume is equal to:

A) The rate of energy leaving the control volume B) The rate of work done by the system C) The rate of heat transfer to the system D) The rate of change of energy within the control volume

14. The Steady Flow Energy Equation (SFEE) is derived based on which fundamental principle?

A) First Law of Thermodynamics B) Second Law of Thermodynamics C) Conservation of Mass D) Conservation of Momentum

15. Which of the following is a key assumption for the Steady Flow Energy Equation?

A) Properties vary with time B) Mass flow rate is constant C) Work transfer is zero D) Heat transfer is zero

16. The SFEE accounts for the energy transfer due to:

A) Internal energy, flow work, kinetic energy, potential energy, heat, and work B) Only internal energy and flow work C) Only heat and work transfer D) Only kinetic and potential energy changes

17. The flow work or flow energy term in the SFEE is represented by:

A) PV B) U C) ΔKE D) ΔPE

18. The SFEE is typically expressed in terms of rates (per unit time) for:

A) Closed systems B) Open systems C) Isolated systems D) Adiabatic systems

19. For a steady flow system with one inlet and one outlet, the SFEE can be written as:

A) h1 + V1^2/2 + gZ1 + Q = h2 + V2^2/2 + gZ2 + W B) u1 + P1V1 + V1^2/2 + gZ1 + Q = u2 + P2V2 + V2^2/2 + gZ2 + W C) Q = ΔU + W D) h1 = h2

20. In the SFEE equation (h1 + V1^2/2 + gZ1 + q = h2 + V2^2/2 + gZ2 + w), what does 'q' represent?

A) Net work done per unit mass B) Heat transfer per unit mass C) Change in internal energy per unit mass D) Change in enthalpy per unit mass

21. For a steady flow process with negligible changes in kinetic and potential energy, the SFEE simplifies to:

A) q = Δh + w B) Δh = q + w C) q = w D) Δh = 0

22. What is the primary application of the Steady Flow Energy Equation?

A) Analyzing chemical reactions B) Analyzing thermodynamic devices like turbines, pumps, and boilers C) Calculating the specific heat of solids D) Determining the phase transition temperatures

23. In a turbine operating under steady flow, the work output is typically:

A) Positive B) Negative C) Zero D) Equal to heat input

24. For a pump operating under steady flow, the work input is typically:

A) Positive B) Negative C) Zero D) Equal to heat output

25. In a boiler operating under steady flow, heat is typically:

A) Added to the system B) Removed from the system C) Zero D) Equal to work done

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

A) Zero B) Maximum C) Minimum D) Infinite

27. For a steady flow adiabatic process with no work interaction, the SFEE reduces to:

A) h1 + V1^2/2 + gZ1 = h2 + V2^2/2 + gZ2 B) h1 = h2 C) V1^2/2 = V2^2/2 D) gZ1 = gZ2

28. What is the term 'flow work' or 'flow energy' fundamentally related to?

A) Internal energy of the fluid B) Kinetic energy of the fluid C) The work required to push the fluid across the control volume boundary D) The potential energy of the fluid

29. If a system is heated and does no work, the change in its internal energy is equal to:

A) The heat supplied B) The work done C) Zero D) The negative of the heat supplied

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

A) Internal Energy B) Flow Energy C) Chemical Energy D) Kinetic Energy

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

A) 70 kJ B) -70 kJ C) 30 kJ D) -30 kJ

32. The term 'steady flow' implies that:

A) The fluid is at rest B) The temperature and pressure are constant throughout C) The properties at any point in the control volume do not change with time D) The flow is reversible

33. 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:

A) Increase B) Decrease C) Remain constant D) Cannot be determined without more information

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

A) Total energy leaving the control volume per unit time B) Rate of heat transfer into the control volume C) Rate of work done by the control volume D) Rate of change of energy within the control volume

35. Which of the following is an intensive property?

A) Mass B) Volume C) Temperature D) Enthalpy

36. Enthalpy (H = U + PV) is a property that is particularly useful for analyzing processes involving:

A) Constant volume heat transfer B) Adiabatic expansion C) Constant pressure heat transfer D) Isothermal compression

37. The flow energy equation is essentially an application of the first law of thermodynamics to:

A) Non-flow systems B) Open systems C) Closed systems D) Isolated systems

38. What is the unit of enthalpy?

A) J/kg B) J C) W D) N

39. 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:

A) ∫PdV B) ∫VdP C) ∫TdS D) ∫(PdV + VdP)

40. In the SFEE, if kinetic and potential energy changes are negligible, and the process is adiabatic (q=0), what does the equation become?

A) h1 = h2 + w B) h1 + w = h2 C) h1 = h2 D) w = 0

41. Which of the following is NOT a form of energy transfer considered in the SFEE?

A) Heat transfer B) Work transfer C) Mass transfer D) Energy carried by mass transfer

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

A) 20 kJ B) -20 kJ C) 80 kJ D) -80 kJ

43. The term gZ in the SFEE represents the change in:

A) Kinetic energy B) Flow energy C) Potential energy D) Internal energy

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

A) Positive B) Negative C) Zero D) Variable

45. The SFEE is applicable to systems where:

A) Mass crosses the boundary B) Mass does not cross the boundary C) Only heat is transferred D) Only work is transferred

46. Which of the following statements is TRUE for a system undergoing an isothermal process (constant temperature) where heat is added?

A) ΔU = Q - W B) ΔU = 0, so Q = W C) ΔU = Q + W D) Q = 0

47. For a steady flow device with negligible heat transfer and negligible changes in kinetic and potential energy, the SFEE reduces to:

A) h1 = h2 + w B) w = h2 - h1 C) h1 = h2 D) w = 0

48. The first law of thermodynamics is a consequence of the principle of:

A) Entropy increase B) Energy conservation C) Mass conservation D) Momentum conservation

49. 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:

A) The net rate of energy carried by mass B) The net rate of change of energy within the control volume C) The rate of internal energy change D) The rate of flow work change

first law of thermodynamics non flow and flow energy equations enthalpy steady flow energy equation - Online Test

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