48. A gas ( γ=1.3) is enclosed in an insulated vessel fitted with insulating piston at a pressure of

10⁵ N/m² . On suddenly pressing the piston the volume is reduced to half the initial volume. The final pressure of the gas is

(a)  2^0.7 ×10⁵                         (b) 2^1.3 ×10⁵

(c)  2^1.4 ×10⁵                          (d)  None of these

Answer-b