A. Simultaneous pressure & temperature change
B. Heating
C. Cooling
D. Both B. and C
Related Mcqs:
- The expression for entropy change given by, ΔS = nR ln (V2/V1) + nCv ln (T2/T1) is valid for ______________________?
A. Reversible isothermal volume change
B. Heating of a substance
C. Cooling of a substance
D. Simultaneous heating and expansion of an ideal gas - Steam undergoes isentropic expansion in a turbine from 5000 kPa and 400°C (entropy = 6.65 kJ/kg K) to 150 kPa) (entropy of saturated liquid = 1.4336 kJ/kg. K, entropy of saturated vapour = 7.2234 kJ/kg. K) The exit condition of steam is_______________?
A. Superheated vapour
B. Partially condensed vapour with quality of 0.9
C. Saturated vapour
D. Partially condensed vapour with quality of 0.1 - The expression for entropy change given by, ΔS = – nR ln (P2/P1), holds good for___________________?
A. Expansion of a real gas
B. Reversible isothermal volume change
C. Heating of an ideal gas
D. Cooling of a real gas - Entropy of a substance remains constant during a/an ____________ change?
A. Reversible isothermal
B. Irreversible isothermal
C. Reversible adiabatic
D. None of these - High pressure steam is expanded adiabatically and reversibly through a well insulated turbine, which produces some shaft work. If the enthalpy change and entropy change across the turbine are represented by ΔH and ΔS respectively for this process ?
A. Δ H = 0 and ΔS = 0
B. Δ H ≠ 0 and ΔS = 0
C. Δ H ≠ 0 and ΔS ≠ 0
D. Δ H = 0 and ΔS ≠ 0 - “At the absolute zero temperature, the entropy of every perfectly crystalline substance becomes zero”. This follows from the __________________?
A. Third law of thermodynamics
B. Second law of thermodynamics
C. Nernst heat theorem
D. Maxwell’s relations - The expression for the work done for a reversible polytropic process can be used to obtain the expression for work done for all processes, except reversible _____________ process?
A. Isobaric
B. Isothermal
C. Adiabatic
D. None of these - Entropy change for an irreversible process taking system and surrounding together is___________________?
A. 0
B. > 0
C. < 0
D. None of these - A system undergoes a change from a given initial state to a given final state either by an irreversible process or by a reversible process, then (where, Δ S1 and Δ SR are the entropy changes of the system for the irreversible and reversible processes respectively) ?
A. Δ S1 is always Δ SR
C. Δ S1 is always > Δ SR
D. Δ S1 is always = Δ SR - Entropy change in case of reversible adiabatic process is________________?
A. Minimum
B. Zero
C. Maximum
D. Indeterminate
