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
The efficiency of Carnot engine is 50% and temperature of 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
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
Universal gas constant is
CP - CV
CP + CV
The internal energy change, when a system goes from state A to B is 40 kJ mole-1. If the system goes from A to B by a reversible path and returns to state A by an irreversible path, what would be the net change in internal energy ?
40 kJ
> 40 kJ
< 40 kJ
zero
P-V plots for two gases during adiabatic processes are shown in figure. Plots 1 and 2 should correspond respectively to
He and O2
O2 and He
He and Ar
O2 and N2
The internal energy change in a system that has absorbed 2 kcal of heat and done 500 J of work is
8900 J
6400 J
5400 J
7900 J
A mono atomic ideal gas, initially at temperature T1 is enclosed in a cylinder fitted with a friction-less piston. The gas is allowed to expand adiabatically to a temperature T2 by releasing the piston suddenly. L1 and L2 are the lengths of the gas column before and after expansion respectively, then T1/T2 is given by
(L1 / L2) 2/3
(L1 / L2)
(L2 / L1)
(L2 / L1)2/3
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
An ideal gas is taken through the cycle A B C A as shown in the figure. If the net heat supplied to the gas in the cycle is 5 J, the work done by the gas in the process C A is
- 5 J
- 10 J
- 15 J
- 20 J