When \( 5 \) moles of He gas expand isothermally and reversibly at \( 300 \, \mathrm{K} \) from \( 10 \, \text{litre} \) to \( 20 \, \text{litre} \), the magnitude of the maximum work obtained is ________ \( \mathrm{J} \).
[nearest integer] (Given : \( R = 8.3 \, \mathrm{J\,K^{-1}\,mol^{-1}} \) and \( \log 2 = 0.3010 \) )