Argon gas is adiabatically compressed to half its volume. If P, V, and T represent the pressure, volume and temperature of the gaseous system, respectively, at any stage, then the correct equation representing the process is : 

TV^-2/5 = constant

For an adiabatic process : PV^\(\gamma\) = constant

TV^\(\gamma\)-1 = constant and T^\(\gamma\)P^1-\(\gamma\) = constant

Putting : \(\gamma\) = 5/3 (argon being a monoatomic gas), 

the equation becomes : PV^5/3 = constant

TV^-2/3 = constant

T^5/3 P^-2/3 = constant

\(\Rightarrow\) TP^-2/5 = constant