first law of thermodynamics non flow and flow energy equations enthalpy steady flow energy equation - Question Bank

1. 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
2. The first law of thermodynamics is a consequence of the principle of:
A) Entropy increase
B) Energy conservation
C) Mass conservation
D) Momentum conservation
3. 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
4. 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
5. 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
6. For a steady flow process through a heat exchanger, what is the typical work transfer (w)?
A) Positive
B) Negative
C) Zero
D) Variable
7. The term gZ in the SFEE represents the change in:
A) Kinetic energy
B) Flow energy
C) Potential energy
D) Internal energy
8. 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
9. 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
10. 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
11. 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)
12. What is the unit of enthalpy?
A) J/kg
B) J
C) W
D) N
13. 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
14. 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
15. Which of the following is an intensive property?
A) Mass
B) Volume
C) Temperature
D) Enthalpy
16. 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
17. 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
18. 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
19. 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
20. 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
21. 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
22. 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
23. 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
24. 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
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. For a pump operating under steady flow, the work input is typically:
A) Positive
B) Negative
C) Zero
D) Equal to heat output
27. In a turbine operating under steady flow, the work output is typically:
A) Positive
B) Negative
C) Zero
D) Equal to heat input
28. 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
29. 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
30. 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
31. 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
32. 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
33. The flow work or flow energy term in the SFEE is represented by:
A) PV
B) U
C) ΔKE
D) ΔPE
34. 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
35. 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
36. 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
37. 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
38. 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
39. For a constant pressure process, the heat transfer is equal to the change in:
A) Internal Energy
B) Enthalpy
C) Entropy
D) Temperature
40. 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
41. What is enthalpy (H) defined as?
A) H = U - PV
B) H = U + PV
C) H = PV - U
D) H = U / PV
42. 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
43. 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
44. 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
45. 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
46. 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
47. 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
48. 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
49. 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
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