entropy

Air inside a rigid, thermally-insulated tank undergoes stirring as shown in the figure below. Which one of the following options is correct?

The fundamental thermodynamic relation for a rubber band is given by $dU = TdS + \tau dL$, where T is the absolute temperature, S is the entropy, $\tau$ is the tension in the rubbe...

An adiabatic vortex tube, shown in the figure given below is supplied with 5 kg/s of air (inlet 1) at 500 kPa and 300 K. Two separate streams of air are leaving the device from out...

Air of mass 1 kg, initially at 300 K and 10 bar, is allowed to expand isothermally till it reaches a pressure of 1 bar. Assuming air as an ideal gas with gas constant of 0.287 kJ/k...

Water flowing at the rate of 1 kg/s through a system is heated using an electric heater such that the specific enthalpy of the water increases by 2.50 kJ/kg and the specific entrop...

For an ideal gas with constant properties undergoing a quasi-static process, which one of the following represents the change of entropy (Δs) from state 1 to 2?

An ideal gas undergoes a process from state 1 ($T_1$= 300 K, $P_1$ = 100 kPa) to state 2 ($T_2$ = 600 K, $P_2$ = 500 kPa). The specific heats of the ideal gas are : $C_p$ = 1 kJ/kg...

One kg of an ideal gas (gas constant, $R = 400$ J/kg. K; specific heat at constant volume, $C_v = 1000$ J/kg. K) at 1 bar, and 300 K is contained in a sealed rigid cylinder. During...

A tank of volume 0.05 m³ contains a mixture of saturated water and saturated steam at 200°C. The mass of the liquid present is 8 kg. The entropy (in kJ/kg K) of the mixture is ____...

A closed system contains $$10$$ $$kg$$ of saturated liquid ammonia at $${10^ \circ }C.$$ Heat addition required to convert the entire liquid into saturated vapour at a constant pre...

An ideal gas of mass $$m$$ and temperature $${T_1}$$ undergoes a reversible isothermal process from an initial pressure $${P_1}$$ to final pressure $$P{}_2.$$ The heat loss during...

In an experimental set-up, air flows between two stations $$P$$ and $$Q$$ adiabatically. The direction of flow depends on the pressure and temperature conditions maintained at $$P$...

One kilogram of water at room temperature is brought into contact with a high temperature thermal reservoir. The entropy change of the universe is

If a closed system is undergoing an irreversible process, the entropy of the system

A heat transformer is a device that transfers a part of the heat, supplied to it at an intermediate temperature, to a high temperature reservoir while rejecting the remaining part...

Considering the relationship $$TdS=dU+PdV$$ between the entropy $$(S),$$ internal energy $$(U),$$ pressure $$(P),$$temperature $$(T)$$ and volume $$(V),$$ Which of the following st...

A certain mass of a pure substance undergoes an irreversible process from state $$1$$ to state $$2,$$ the path of the process being a straight line on the $$T$$-$$s$$ diagram. Calc...

For an ideal gas the expression $$\left[ {T{{\left( {{{\delta s} \over {\delta T}}} \right)}_p} - T{{\left( {{{\delta s} \over {\delta T}}} \right)}_v}} \right]$$ is always equal t...

A system undergoes a state change from $$1$$ to $$2.$$ According to the second law of thermodynamics, for the process to be feasible, the entropy changes, $${S_2} - {S_1}$$ of the...

A $$1500$$ $$W$$ electrical heater is used to heat $$20$$ $$kg$$ of water $$\left( {{C_p} = 4186\,\,J/kg\,\,K} \right)$$ in an insulated bucket, from a temperature of $${30^{^0}}C$...