The energy equivalent of 3.2 gm of substance in MeV is

The correct answer is Option (2) → \( 1.8\times10^{27} \)

By Einstein’s mass–energy relation, \( E = mc^{2} \); the answer is then converted from joules to MeV using \( 1\,\mathrm{MeV} = 1.6\times10^{-13}\,\mathrm{J} \).

    \( m = 3.2\,\mathrm{g} = 3.2\times10^{-3}\,\mathrm{kg} \)

    \( E = (3.2\times10^{-3}\,\mathrm{kg})(3\times10^{8}\,\mathrm{m\,s^{-1}})^{2} = 2.88\times10^{14}\,\mathrm{J} \)

    \( \displaystyle E = \frac{2.88\times10^{14}}{1.6\times10^{-13}}\,\mathrm{MeV} = 1.8\times10^{27}\,\mathrm{MeV} \)

Note: NTA picked this question from an NCERT (2026-27) example and changed the figures. Do not ignore NCERT while practising numericals.

NCERT (2026-27):
Mass – Energy – …