Question

How much amount of energy is liberated in converting $1kg$ of coal into energy?

• A. $9\times 10^{16}J$
• B. $9\times 10^{15}J$
• C. $3\times 10^{14}J$
• D. $4\times 10^{6}J$

Answer 1

Answer: (A)

According to mass-energy equivalence,
$E=m{c}^2=1\times {\left(3\times 10^8\right)}^2$
$=9\times 10^{16}J$
So, $9\times 10^{16}J$ of energy is liberated in converting $1kg$ of coal into energy.