Calculate the energy emitted when electrons of $2.0 \mathrm{g}$ atom of hydrogen undergo transition giving the spectral lines of lowest energy in the visible region of its atomic spectra.

${\mathrm{R}}_{\mathrm{H}}=1.1\times {10}^7{\mathrm{m}}^{-1};\mathrm{C}=3\times {10}^8\mathrm{m}/\sec ;\mathrm{h}=6.625\times {10}^{-34}\mathrm{J}.\sec$