Thermodynamics ...

A sample of a diatomic gas at pressure $$p$$, volume $$V$$ and temperature $$T$$ is compressed to $$V/2$$ isothermally. Its pressure is found to be $$p_{i}$$. If it is compressed to $$V/2$$ adiabatically, its pressure comes out to be $$p_{a}$$. What is the relation between $$p_{i}$$ and $$p_{a}$$?

A sample of diatomic gas at pressure p, volume V and temperature T is compressed to V/2 isothermally. Its pressure is found to be $${p}_{i}$$. If it is compressed to V/2 adiabaticaly, its pressure comes out to be $${p}_{a}$$. What is the relation between $${p}_{i}$$ and $${p}_{a}$$?

Three stars A, B, C have surface temperatures $$T_A$$, $$T_B$$ and $$T_C$$. A appears bluish, B appears reddish and C appears yellowish. We can conclude that:

Which of the following P-V diagram representing the graph of isomeric process?

A sample of ideal gas $$ (\gamma = 1.4) $$ is heated at constant pressure. If an amount of $$100\ J$$ heat is supplied to the gas, the work done by the gas is

The possibility of increase in the temperature of a gas without adding heat to it happens in :

Match the column I with column II         
Types of processes                    Features
(A)Isothermal                           (p)   $$\Delta$$ Q = 0
(B)Isobaric                                (q)   Volume constant
(C)Isochoric                              (r)    Pressure constant
(D)Adiabatic                             (s)    Temperature constant

A heat insulating cylinder with a movable piston contains 5 moles of hydrogen at standard temperature and pressure if the gas is compressed to quarter of its original volume when the pressure of the gas is increased by ($$\gamma$$ = 1.4 )   

Let $$E_D, E_P, E_S$$ denote efficiency of a diesel, a petrol and a steam engine respectively. which of the following is correct?

The most efficient engine is?