A Carnot engine whose sink is at 300 K has an efficiency of 40%. By how much should the temperature of source be increased so as to increase its efficiency by 50% of original efficiency?
275 K
325 K
250 K
380 K
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
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 molar specific heat at constant pressure of an ideal gas is (7/2)R. The ratio of specific heat at constant pressure to that at constant volume is
7/5
8/7
5/7
9/7
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
An ideal mono atomic gas is taken round the cycle ABCDA as shown in the P-V diagram.
PV
2 PV
PV / 2
zero
A scientist says that the efficiency of his heat engine which works at source temperature of 127oC and sink temperature 27oC is 26%.
It is possible but less probable
It is quite possible
Data is incomplete
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.
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
One mole of a mono atomic gas is heated at a constant pressure of 1 atmosphere from 0 K to 100 K. If the gas constant R = 8.32J/mol K, the change in internal energy of the gas is approximately.
2.3 J
46 J
8.67 x 103 J
1.25 x 103 J