When amplitude is at its extremum values the energy of the wave will also be maximum. Hence, it will have maximum energy at antinodes, When amplitude is zero, the energy will also be zero and is the least possible value for energy. Hence, it will have minimum energy at nodes.
(વાયુનો અચળાંક $R=8.3 \;JK ^{-1} mol ^{- 1}$ લો)