Which statement is incorrect ?
all reversible cycles have same efficiency
reversible cycle has more efficiency than an irreversible one
Carnot cycle is a reversible one
Carnot cycle has the maximum efficiency of all the cycles
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.
A diatomic ideal gas is used in a Carnot engine as the working substance. If during the adiabatic expansion part of the cycle the volume of the gas increased from V to 32 V, the efficiency of the engine is
0.25
0.5
0.75
0.99
A Carnot engine, having an efficiency of 1/10 as heat engine, is used as a refrigerator. If the work done on the system is 10 J, the amount of energy absorbed from the reservoir at lower temperature is
1 J
90 J
99 J
100 J
We consider a thermodynamic system. If ΔU represents the increase in its internal energy and W the work done by the system, which of the following statements is true?
ΔU = - W in an adiabatic process
ΔU = W in an isothermal process
ΔU = - W in an isothermal process
ΔU = W in an adiabatic process
A thermodynamic process is shown in the figure. The pressure and volumes corresponding to some points in the figure are
PA = 3 × 104 Pa, VA = 2 × 10-3 m3
PB = 8 × 104 Pa, VB = 5 × 10-3 m3
In process AB, 600 J of heat is added to the system and in process BC, 200 J of heat is added to the system. The change in internal energy of the system in process AC would be
560 J
800 J
600 J
640 J
An ideal gas undergoing an adiabatic change has the following pressure-temperature relationship
pγ-1Tγ = constant
pγTγ-1 = constant
pγT1-γ = constant
p1-γTγ = constant
In an adiabatic process, the state of a gas is changed from P1, V1, T1 to P2, V2, T2. Which of the following relations is correct ?
The temperature-entropy diagram of a reversible engine cycle is given in the figure. Its efficiency is
1/3
1/2
2/3
1/4
In an adiabatic process, the quantity which remains constant is
Volume
Pressure
Temperature
Total heat of the system
