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

   A. +ve
   B. 0
   C. -ve
   D. ∞

3. 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

4. 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

5. 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

6. A solid metallic block weighing 5 kg has an initial temperature of 500°C. 40 kg of water initially at 25°C is contained in a perfectly insulated tank. The metallic block is brought into contact with water. Both of them come to equilibrium. Specific heat of block material is 0.4 kJ.kg-1. K-1. Ignoring the effect of expansion and contraction and also the heat capacity to tank, the total entropy change in kJ.kg-1, K-1 is_________________?

   A. -1.87
   B. 0
   C. 1.26
   D. 3.91

7. For an isothermal reversible compression of an ideal gas_______________?

   A. Only ΔE = 0
   B. Only ΔH =0
   C. ΔE = ΔH = 0
   D. dQ = dE

8. Entropy change in case of reversible adiabatic process is________________?

   A. Minimum
   B. Zero
   C. Maximum
   D. Indeterminate

9. The change in __________ is equal to the reversible work for compression in steady state flow process under isothermal condition?

   A. Internal energy
   B. Enthalpy
   C. Gibbs free energy
   D. Helmholtz free energy

10. The internal energy of an ideal gas does not change in a reversible _____________ process?

    A. Isothermal
    B. Adiabatic
    C. Isobaric
    D. Isometric