Question

The energy equivalent to a substance of mass $1 \, g$ is

• A. $18\times 10^{13} \, J$
• B. $9\times 10^{13}J$
• C. $ \, 18\times 10^{6}J$
• D. $9\times 10^{6}J$

Answer 1

Answer: (B)

Given, $m=1 \, g=10^{- 3 \, }kg$
Energy, $E=mc^{2}$
$\therefore $ Energy equivalent $=\left(10\right)^{- 3}\times \left(3 \times \left(10\right)^{8}\right)^{2}$
$\left(\because c = 3 \times \left(10\right)^{8} \, m \left( \, s\right)^{- 1}\right)$
$=9\times 10^{13} \, J$