One mole of ideal gas expands isobarically to double its volume at 27°C. Then the work done by the gas is nearly

$\begin{array}{rl}\mathrm{W}& =\mathrm{PdV}=\mathrm{nRdT} ( \mathrm{in} \mathrm{isobaric} \mathrm{process} \mathrm{if} \mathrm{volume} \mathrm{is} \mathrm{doubled} \mathrm{temperature} \mathrm{also} \\ & \mathrm{becomes} \mathrm{double} \mathrm{so} \mathrm{dT}=\mathrm{T})\\ & =1\times 2\times 300\\ & =600\mathrm{cal}\end{array}$