MCQ on Thermodynamics JE Mecjanical Part 2
36. Which equation is the CORRECT representation of the process shown below?
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37. For a process which is non-flow, the first law of thermodynamics states_______.
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(a) dU= Q - W (b) dU= Q + W
(c) dH = Q - W (d) dH= Q +W
38. What happens when the heat supplied to the system is more than the work transfer out of the system?
(a) Constant internal energy
(b) Decrease in internal energy
(c) Increase in internal energy
(d) Internal energy cannot be determined |
39. Which formula is the CORRECT depiction of slope of adiabatic curve?
| 40. What is the drop in enthalpy (in kJ/kg) for a steam whistle which is perfectly insulated and does not work has an exit velocity of steam at 40 m/sec? |
(a) 0.8 (b) 8
(c) 80 (d) 800
Ans : (a)
41. A gas is compressed frictionless from an initial state of y m3 and 1 MPa to a final state of 0.2 m3 and 1 MPa. There is a transfer of 40 kJ of heat from the gas and a drop of 20 kJ in internal energy. What is the initial state volume of the gas?
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(a) 0.2 (b) 0.22
(c) 19.8 (d) 20.2
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Ans : (b)
42. Which equation best describes the first law of thermodynamics?
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(a) ∂q = ∂u + ∂w (b) ∂q = ∂u – ∂w
(c) ∂q = ∂w – ∂u (d) ∂u = ∂q + ∂w
Ans : (a)
43. The internal energy of the system is a function of temperature only U= 30+0.5t kJ. If the system does the work of 0.5 kJ/K, What is the increase interaction per degree temperature? (a) -1
(b) 0
(c) 1
(d) cannot be determined
44. The work done by a system is 45 kJ. If the internal energy of the system is decreased by 15 kJ. What is the heat received (in kJ) by the system?
(a) –60 (b) –30
(c) 30 (d) 60
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46. Which equation clearly defines the entropy change during the isothermal process for a system with m kg of gas at pressure P1, volume V1, temperature T1 and entropy S1 is heated to state points of pressure P2, volume V2, temperature T2 and entropy S2?
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47. What is the fundamental unit of enthalpy?
(a) ML2T–2 (b) ML–2T–1
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(c) ML–2T–2 (d) ML–3T2
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