A Carnot engine operating between temperatures T1 and T2 has efficiency 1/6. When T2 is lowered by 62 K, its efficiency increases to 1/3. Then T1 and T2 are, respectively
372 K and 310 K
372 K and 330 K
330 K and 268 K
310 K and 248 K
The PT diagram for an ideal gas is shown in the figure, where AC is an adiabatic process. Find the corresponding PV diagram.
Which of the following statement is correct for any thermodynamic system ?
The internal energy changes in all processes
Internal energy and entopy are state functions
The change in entropy can never be zero
The work done in an adiabatic process is always zero.
An ideal gas heat engine is operating between 227oC and 127oC. It absorbs 104 J of heat at the higher temperature. The amount of heat converted into work is
2000 J
4000 J
8000 J
5600 J
A gas at state A changes to state B through path I and II shown in figure. The changes in internal energy are ΔU1 and ΔU2 respectively. Then
Δ U1 > ΔU2
Δ U1 < ΔU2
Δ U1 = ΔU2
Δ U1 = ΔU2 = 0
100 g of water is heated from 30oC to 50oC. Ignoring the slight expansion of the water, the change in its internal energy is (specific heat of water is 4184 J/kg/K)
4.2 kJ
8.4 kJ
84 kJ
Which is an intensive property ?
volume
mass
refractive index
weight
A system goes from A to B via two processes I and II as shown in the figure. If ΔU1 and ΔU2are the changes in internal energies in the processes I and II respectively, then
ΔU1 = ΔU2
ΔU1 > ΔU2
ΔU1 < ΔU2
relation between ΔU1 and ΔU2 cannot be determined.
The temperature of source and sink of a heat engine are 127oC and 27oC respectively. An inventor claims its efficiency to be 26%, then
It is impossible
It is possible with high probability
It is possible with low probability
Data are insufficient
The volume (V) versus temperature (T) graphs for a certain amount of a perfect gas at two pressures P1 and P2are shown in the figure. It follows from the graph that
P1 > P2
P1 < P2
P1 = P2
information is insufficient to draw any conclusion.
