Q146 / 180 · COMEDK 2014 · Physics
The energy equivalent of $1 \mathrm{~g}$ of a substance is
- A$4.5 \times 10^{13} \mathrm{~J}$
- B$9 \times 10^{16} \mathrm{~J}$
- Correct answerC$9 \times 10^{13} \mathrm{~J}$
- D$18 \times 10^{13} \mathrm{~J}$
Solution
Given, $m=1 \mathrm{~g}=10^{-3} \mathrm{~kg}$
According to Einstein's mass-energy equation,
$$
E=m c^{2}=10^{-3} \times\left(3 \times 10^{8}\right)^{2}=9 \times 10^{13} \mathrm{~J}
$$
Hence, the correct answer is option: 'C'.