An ideal gas heat engine is operating between 227oC and 127oC. It absorbs 104 J of heat at the higher temperature. The amount of heat converted into work is
2000 J
4000 J
8000 J
5600 J
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
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
Which of the following parameters does not characterize the thermodynamic state of matter ?
Temperature
Pressure
Work
Volume
An ideal gas undergoing adiabatic change has the following pressure-temperature relationship
pγ-1Tγ = constant
pγTγ-1 = constant
pγT1-γ = constant
p1-γTγ = constant
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
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 is incorrect regarding the first law of thermodynamics ?
It introduces the concept of the internal energy
It introduces the concept of the entropy
It is not applicable to any cyclic process
It is restatement of the principle of conservation of energy
In an adiabatic process, the state of a gas is changed from P1, V1, T1 to P2, V2, T2. Which of the following relations is correct ?
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
