Q.

One mole of an ideal gas expands adiabatically from an initial state (TA,V0) to final state (Tf,5V0). Another mole of the same gas expands isothermally from a different initial state (TB,V0) to the same final state (Tf,5V0). The ratio of the specific heats at constant pressure and constant volume of this ideal gas is γ. What is the ratio TA/TB                         [2023]

1 5γ-1  
2 51-γ  
3 5γ  
4 51+γ  

Ans.

(1)

For adiabatic process TVγ-1=constant

  TAV0γ-1=Tf(5V0)γ-1           ...(i)

and for isothermal process, no change in temperature

  TB=Tf                ...(ii)

Dividing (i) by (ii)

TATB=5γ-1