The energy equivalent of 10 g of substance is

The correct answer is Option (3) → \( 9\times10^{14}\,\mathrm{J} \)

By Einstein's mass-energy relation a mass \( m \) is equivalent to the energy \( E = mc^{2} \).

    \( m = 10\,\mathrm{g} = 10^{-2}\,\mathrm{kg} \)
    \( c = 3\times10^{8}\,\mathrm{m\,s^{-1}} \)

    \( \displaystyle E = mc^{2} = 10^{-2} \times (3\times10^{8})^{2} = 10^{-2} \times 9\times10^{16} = 9\times10^{14}\,\mathrm{J} \)

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 – …