Question 112: Atoms & Nuclei

Question

The energy equivalent of $1 \mathrm{~g}$ of substance is :

Accepted Answer

To determine the energy equivalent of a mass, we use Einstein's mass-energy equivalence principle given by the equation:
$E = mc^2$
where:
- $E$ is the energy
- $m$ is the mass
- $c$ is the speed of light in a vacuum, which is approximately $3 	imes 10^8 \mathrm{~m/s}$
Given the mass $m = 1 \mathrm{~g} = 1 	imes 10^{-3} \mathrm{~kg}$, we can substitute these values into the equation:
$E = (1 	imes 10^{-3} \mathrm{~kg}) 	imes (3 	imes 10^8 \mathrm{~m/s})^2$
Calculating this, we get:
$E = 1 	imes 10^{-3} 	imes 9 	imes 10^{16}$
$E = 9 	imes 10^{13} \mathrm{~J}$
Next, to convert this energy into electron volts ($\mathrm{eV}$), we use the conversion factor: $1 \mathrm{~J} = 6.242 	imes 10^{12} \mathrm{~MeV}$.
Therefore:
$E = 9 	imes 10^{13} \mathrm{~J} 	imes 6.242 	imes 10^{12} \mathrm{~MeV/J}$
Calculating this, we get:
$E = 5.6178 	imes 10^{26} \mathrm{~MeV}$
Therefore, the energy equivalent of $1 \mathrm{~g}$ of a substance is:
Option A:
$5.6 	imes 10^{26} \mathrm{~MeV}$

Answer

$5.6 	imes 10^{26} \mathrm{~MeV}$

Answer

$5.6 	imes 10^{12} \mathrm{~MeV}$

Answer

$5.6 \mathrm{~eV}$

Answer

$11.2 	imes 10^{24} \mathrm{~MeV}$

Atoms & Nuclei

The energy equivalent of 1 \mathrm{~g} of substance is :

Choose the correct answer: