First law of thermodynamics is a consequence of conservation of
Work
Energy
Heat
All of these
An engine has an efficiency of 1/6. When the temperature of sink is reduced by 62oC, its efficiency is doubled. Temperature of the source is
124oC
37oC
62oC
99oC
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
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 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
Which one of the following is not a state function ?
temperature
entropy
pressure
work
P-V plots for two gases during an 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
Which one is correct ?
In an isobaric process, ΔP = 0
In an isochoric process, ΔW = 0
In an isothermal process, ΔT = 0
In an adiabatic process, ΔQ = 0
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 that
P1 > P2
P1 < P2
P1 = P2
information is insufficient to draw any conclusion.
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
