1
GATE ME 2000
Subjective
+5
-0
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. Calculate heat transfer & work done. Some of the properties at the initial and final states are:
$${T_1} = 330\,K,\,\,{T_2} = 440\,K;\,\,{U_1} = 170\,kJ,\,\,$$
$$\,{U_2} = 190\,kJ;\,\,{H_1} = 220{\,_{}}kJ,\,\,{H_2} = 247\,kJ,$$
and $${S_1} = 0.23\,kJ/K$$ and $${S_2} = 0.3\,kJ/K$$ where $$T, U, H$$ and $$S$$ represent temperature, internal energy, enthalpy and entropy respectively.
2
GATE ME 2000
MCQ (More than One Correct Answer)
+2
-0
For a compressible fluid, sonic velocity is
A
a property of the fluid
B
always given by $${\left( {\gamma RT} \right)^{{\raise0.5ex\hbox{$\scriptstyle 1$} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{$\scriptstyle 2$}}}}$$ where $$\gamma $$, $$R$$ and $$T$$ are respectively the ratio of specific heats, gas constant and temperature in $$K$$
C
always given by $${\left( {\partial p/\partial \rho } \right)_s}^{{\raise0.5ex\hbox{$\scriptstyle 1$} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{$\scriptstyle 2$}}}.$$ Where $$P,$$ $$\rho $$ and $$s$$ are respectively pressure, density and entropy
D
always greater than the velocity of fluid at any location.
3
GATE ME 2000
MCQ (Single Correct Answer)
+1
-0.3
A steam turbine receives steam steadily at $$10$$ $$bar$$ with an enthalpy of $$3000$$ $$kJ/kg$$ and discharges at $$1$$ bar with an enthalpy of $$2700$$ $$kJ/kg.$$ The work output is $$250$$ $$kJ/kg.$$ The changes in kinetic and potential energies are negligible. The heat transfer from the turbine casing to the surroundings is equal to
A
$$0$$ $$kJ$$
B
$$50$$ $$kJ$$
C
$$150$$ $$kJ$$
D
$$250$$ $$kJ$$
4
GATE ME 2000
MCQ (More than One Correct Answer)
+2
-0
When an ideal gas with constant specific heats is throttled adiabatically, with negligible changes in kinetic and potential energies
A
$$\Delta h = 0,\,\,\Delta T = 0$$
B
$$\Delta h > 0,\,\,\Delta T = 0$$
C
$$\Delta h > 0,\,\,\Delta s > 0$$
D
$$\Delta h = 0,\,\,\Delta s > 0$$