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
Initial pressure and volume of a gas are P and V respectively. First the gas is expanded isothermally to 4V and then its volume is made V by adiabatic process. Its final pressure (γ = 1.5) is
8 P
4 P
P
2 P
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
One mole of a monoatomic 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
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
An ideal gas undergoing adiabatic change has the following pressure-temperature relationship
pγ-1Tγ = constant
pγTγ-1 = constant
pγT1-γ = constant
p1-γTγ = constant
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 Carnot engine operating between temperatures T1 and T2 has efficiency 1/6. When T2 is lowered by 62 K, its efficiency increases to 1/3. Then T1 and T2 are, respectivley:
372 K and 310 K
372 K and 330 K
330 K and 268 K
310 K and 248 K
If cp and cv denote the specific heat of nitrogen per unit mass at constant pressure and constant volume respectively, then:
cp - cv = R/28
cp - cv = R/14
cp - cv = R
cp - cv = 28R
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
