A thermodynamic system is taken through the cycle PQRSP process. The net work done by the system is :
20 J
-20 J
400 J
-374 J
Which one is correct ?
In an isobaric process, ΔP = 0
In an isochoric process, ΔW = 0
In an isothermal process, ΔT = 0
In an isothermal process, ΔQ = 0
Which one of the following is not a state function ?
Temperature
Entropy
Pressure
Work
The efficiency of a Carnot engine is 50% and temperature of the sink is 500 K. If the temperature of source is kept constant and its efficiency is to be raised to 60%, then the required temperature of the sink will be:
600 K
500 K
400 K
100 K
Even Carnot engine cannot give 100% efficiency, because we cannot :
Prevent radiation
Find ideal sources
Reach absolute zero temperature
Eliminate friction
Which of the following is not a thermodynamic coordinate?
P
V
T
R
An ideal gas undergoing adiabatic change haswhich of the following pressure-temperature relationship ?
pγ-1Tγ = constant
pγTγ-1 = constant
pγT1-γ = constant
p1-γTγ = constant
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.
An ideal gas initially at P1, V1 is expanded to P2, V2 and then compressed adiabatically to the same volume V1 and pressure P3. If W is the net work done by the gas in complete process, which of the following is true ?
W > 0 ; P3 > P1
W < 0 ; P3 > P1
W > 0 ; P3 < P1
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.
