Nuclei - Result Question 21
23. The energy equivalent of $0.5 g$ of a substance is :
(a) $4.5 \times 10^{13} J$
(b) $1.5 \times 10^{13} J$
(c) $0.5 \times 10^{13} J$
(d) $4.5 \times 10^{16} J$
[2020]
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Answer:
Correct Answer: 23. (a)
Solution:
- (a) From the Einstein’s mass-energy equivalence, the relation between the mass of a substance $m$ and its energy $E$ is
$E=m c^{2}$
Here, $c=$ speed of light
$ \begin{aligned} \therefore E & =0.5 \times 10^{-3} \times(3 \times 10^{8})^{2}=0.5 \times 10^{-3} \times 9 \times 10^{16} \\ & =4.5 \times 10^{13} J . \end{aligned} $
