What would be the amount of energy released if 1 g of a substance is converted to energy? (Given, speed of light in vacuum = \( 3\times10^{8}\,\mathrm{m\,s^{-1}} \))
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → \( 9\times10^{13} \) J
By Einstein’s mass-energy relation \( E = mc^{2} \), the energy equivalent of a mass \( m \) is found after converting the mass to kg: \( 1\,\mathrm{g} = 10^{-3}\,\mathrm{kg} \).
\( E = mc^{2} = (1\times10^{-3}\,\mathrm{kg})\times(3\times10^{8}\,\mathrm{m\,s^{-1}})^{2} = 9\times10^{13}\,\mathrm{J} \)
Note: This question is from NCERT (2026-27). NTA sets numerical questions from NCERT too, so do not ignore NCERT while practising numericals.
NCERT (2026-27):
Mass – Energy – …
