A. its internal energy (U) decreases and its entropy (S) increases
B. U and S both decreases
C. U decreases but S is constant
D. U is constant but S decreases
Related Mcqs:
- 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 - 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 - 1m3 of an ideal gas at 500 K and 1000 kPa expands reversibly to 5 times its initial volume in an insulated container. If the specific heat capacity (at constant pressure) of the gas is 21 J/mole . K, the final temperature will be ?
A. 35 K
B. 174 K
C. 274 K
D. 154 K - Heat capacity of air can be approximately expressed as, Cp = 26.693 + 7.365 x10-3 T, where, Cp is in J/mole.K and T is in K. The heat given off by 1 mole of air when cooled at atmospheric pressure from 500°C to – 100°C is ____________________?
A. 10.73 kJ
B. 16.15 kJ
C. 18.11 kJ
D. 18.33 kJ - A two stage compressor is used to compress an ideal gas. The gas is cooled to the initial temperature after each stage. The intermediate pressure for the minimum total work requirement should be equal to the _____________ mean of P1 and P2.(where, P1 and P2 are initial and final pressures respectively) ?
A. Logarithmic
B. Arithmetic
C. Geometric
D. Harmonic - When a gas is subjected to adiabatic expansion, it gets cooled due to__________________?
A. Decrease in velocity
B. Decrease in temperature
C. Decrease in kinetic energy
D. Energy spent in doing work - A domestic refrigerator has a/an ____________ cooled condenser?
A. Water
B. Air
C. Evaporative
D. Gas - Gases are cooled in Joule-Thomson expansion, when it is _____________ inversion temperature?
A. Below
B. At
C. Above
D. Either B. or C. - A cyclic engine exchanges heat with two reservoirs maintained at 100 and 300°C respectively. The maximum work (in J) that can be obtained from 1000 J of heat extracted from the hot reservoir is_________________?
A. 349
B. 651
C. 667
D. 1000 - 4 kg moles of an ideal gas expands in vacuum spontaneously. The work done is_________________?
A. 4 J
B. ∞
C. 0
D. 8 J
