a
Given, $V_{1}=V$
$V_{2}=2 V$
$T_{1}=27^{\circ}+273=300 \mathrm{K}$
$T_{2}=?$
From charle's law
$\frac{V_{1}}{T_{1}}=\frac{V_{2}}{T_{2}}(\because \text { Pressure is constant })$
or, $\quad \frac{V}{300}=\frac{2 V}{T_{2}}$
$\therefore \quad T_{2}=600 \mathrm{K}=600-273=327^{\circ} \mathrm{C}$