$A$ cycle tyre bursts suddenly. What is the type of this process?

The $P-V$ graph of an ideal gas cycle is shown. The adiabatic process is described by the region

$A$ monoatomic ideal gas,initially at temperature $T_1$,is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature $T_2$ by releasing the piston suddenly. $L_1$ and $L_2$ are the lengths of the gas columns before and after the expansion,respectively. The ratio $T_2 / T_1$ is

$A$ gas is being compressed adiabatically. The specific heat of the gas during compression is

$Assertion :$ Adiabatic expansion is always accompanied by fall in temperature.
$Reason :$ In adiabatic process, volume is inversely proportional to temperature.

The adiabatic elasticity of a diatomic gas at $NTP$ is ........ $N/m^2$.