A Carnot engine, having an efficiency of 1/10 as a 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
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.
Which of the following is not a thermodynamic coordinate?
P
V
T
R
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.
"Heat cannot itself flow from a body at lower temperature to a body at higher temperature" is a statement related to:
Second law of thermodynamics
Conservation of momentum
Conservation of mass
First law of thermodynamics
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 :
P1 > P2
P1 < P2
P1 = P2
information is insufficient to draw any conclusion.
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
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 engine has an efficiency of 1/6. When the temperature of sink is reduced by 62oC, its efficiency is doubled. The temperature of the source is:
124oC
37oC
62oC
99oC
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
