A sample of 1 mole gas at temperature $T$ is adiabatically expanded to double its volume. If adiabatic constant for the gas is $\gamma = \frac { 3 } { 2 }$, then the work done by the gas in the process is:\\
(1) $\frac { R } { T } [ 2 - \sqrt { 2 } ]$\\
(2) $\frac { T } { R } [ 2 + \sqrt { 2 } ]$\\
(3) RT $[ 2 - \sqrt { 2 } ]$\\
(4) $\mathrm { RT } [ 2 + \sqrt { 2 } ]$