Q.1
A car uses power ofhp for a one hour in a round trip. Thermal efficiency ofcan be assumed? Find the change in entropy if we assume ambient at 20°C.
  • a) 354.1 kJ/K
  • b) 654.1 kJ/K
  • c) 254.1 kJ/K
  • d) 554.1 kJ/K
Q.2
If heat Q flows reversibly from the system to the surroundings at To, what will be the effect on entropy?
  • a) entropy of the system is reduced by Q/To
  • b) system has lost entropy to the surroundings
  • c) entropy increase of the surroundings is Q/To
  • d) all of the mentioned
Q.3
The entropy of any closed system can increase in which of the following way?
  • a) dissipative effects or internal irreversibilities
  • b) by heat interaction in which there is entropy transfer
  • c) both of the mentioned
  • d) none of the mentioned
Q.4
A hot metal piece is cooled rapidly to 25°C, removingkJ from the metal. Calculate the change of entropy if saturated liquid R-at −20°C absorbs the energy so that it becomes saturated vapor.
  • a) 0.950 kJ/K
  • b) 7.950 kJ/K
  • c) 3.950 kJ/K
  • d) 5.950 kJ/K
Q.5
The entropy change of a system between two identifiable equilibrium state is ___ when the intervening process is reversible or change of state is irreversible.
  • a) depends on the process
  • b) different
  • c) same
  • d) none of the mentioned
Q.6
When work is dissipated into internal energy, what is the change in the disorderly motion of molecules.
  • a) increases
  • b) remains the same
  • c) decreases
  • d) none of the mentioned
Q.7
Which of the following is an example of low grade energy?
  • a) heat from combustion of fossil fuel
  • b) heat or thermal energy
  • c) heat from nuclear fission or fusion
  • d) all of the mentioned
Q.8
The available energy of a system ___ as its temperature or pressure decreases and approaches that of the surroundings.
  • a) remains constant
  • b) increases
  • c) decreases
  • d) none of the mentioned
Q.9
Which of the following is true?
  • a) Q for reversible < Q for irreversible and work for reversible < work for irreversible
  • b) Q for reversible > Q for irreversible and work for reversible < work for irreversible
  • c) Q for reversible < Q for irreversible and work for reversible > work for irreversible
  • d) Q for reversible > Q for irreversible and work for reversible > work for irreversible
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