Entropy change in case of reversible adiabatic process is________________?

Related Mcqs:

1. On a P-V diagram of an ideal gas, suppose a reversible adiabatic line intersects a reversible isothermal line at point A. Then at a point A, the slope of the reversible adiabatic line (∂P/∂V)s and the slope of the reversible isothermal line (∂P/∂V)T are related as (where, y = Cp/Cv) ?

   A. (∂P/∂V)S = (∂P/∂V)T
   B. (∂P/∂V)S = [(∂P/∂V)T]Y
   C. (∂P/∂V)S = y(∂P/∂V)T
   D. (∂P/∂V)S = 1/y(∂P/∂V)T

2. 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

3. 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

4. The entropy change in a reversible isothermal process, when an ideal gas expands to four times its initial volume is_________________?

   A. R loge 4
   B. R log10 4
   C. Cv log10 4
   D. Cv loge 4

5. Specific heat of a gas for a reversible adiabatic process is________________?

   A. Negative
   B. Zero
   C. Infinity
   D. None of these

6. During a reversible isothermal expansion of an ideal gas, the entropy change is_________________?

   A. +ve
   B. 0
   C. -ve
   D. ∞

7. During a reversible isothermal expansion of an ideal gas, the entropy change is___________________?

   A. +ve
   B. 0
   C. -ve
   D. ∞

8. 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

9. 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

10. Which of the following is not correct for a reversible adiabatic process ?

    A. TVγ-1 = constant
    B. p1-γ.TY = constant
    C. PVγ = constant
    D. None of these