Thermodynamics Mid - I, September - 2014

1.For a polytropic process (pVn = C), the work done during an expansion is
  • P2V2 – P1V1
  • (P2V2 – P1V1)/(n+1)
  • (P2V2 – P1V1)/(n-1)
  • (P1V1 – P2V2)/(n-1)
Answer: D
2.Isothermal and adiabatic processes become identical at
  • The saturation temperature
  • the absolute zero
  • 0o C
  • The triple point
Answer: B
3.The internal energy of an ideal gas is a function of
  • pressure only
  • volume only
  • absolute temperature only
  • entropy only
Answer: C
4.No heat engine can operate by exchanging heat from a single temperature source. This is
  • the Kelvin-Plank statement
  • Joule statement
  • the Clausius statement
  • None
Answer: A
5.In a Carnot cycle , the addition and rejection of heat take place at
  • Constant pressure
  • constant volume
  • constant temperature
  • constant enthalpy
Answer: C
6.A perfect gas, enclosed in a cylinder-piston assembly undergoes a reversible adiabatic expansion. As such its
  • ΔS = 0
  • (ΔSSYS +ΔSSURR = 0
  • ΔSSURR = 0
  • entropy will increase
Answer: A
7.Entropy change of a closed system undergoing an adiabatic process is
  • 0
  • Less than
  • More than 0
  • none of the above
Answer: A
8.A system is said to be in the dead state when it is in
  • Thermal equilibrium with the environment
  • chemical equilibrium with the environment
  • mechanical equilibrium with the environment
  • thermodynamic equilibrium with the environment
Answer: D
9.The state of a substance whose evaporation from its liquid state is complete, is known as
  • Vapour
  • Perfect gas
  • Air
  • Steam
Answer: B
10.The equation of state of an ideal gas is a relationship between the variables
  • Pressure and volume
  • Pressure and temperature
  • Pressure , volume and temperature
  • None of the above
Answer: C
11.The energy of an isolated system during a process is always __________
Answer: Decreases
12.Energy transfer as heat is always accompanied by a flow of ___________
Answer: Entropy
13.In statistical thermodynamics , entropy is defined as __________
Answer: The degree of randomness
14.In an irreversible process there is a _________ of heat
Answer: Loss
15.The value of one bar (in SI Units) is equal to __________
Answer: 1 * 105 N/m2
16.The ________ law of thermodynamics asserts that energy has quality as well as quantity.
Answer: Second
17.Both heat and work transfers are _________ functions and hence they are _______ differentials.
Answer: Path, inexact
18.Work done in a free expansion process is ____________
Answer: Zero
19.__________ is the maximum portion of energy which could be converted into useful work by ideal processes which reduce the system to a dead state.
Answer: Available energy
20.Coefficient of performance of heat pump(COPHP) = 1 + _________
Answer: COPR