The energy equivalent of mass associated with the rest mass of an electron is nearly:

Question

Question

This question was previously asked in

AAI ATC Junior Executive 27 July 2022 Shift 3 Official Paper

Answer 1

Concept:

Albert Einstein proposed the famous equation that relates mass and energy.
According to this equation, mass can be converted into energy and vice versa.
Equation: E = mc² where E = kinetic energy of the body, m = relativistic mass, c = speed of light
This equation is the basis of the theory of special relativity which say as an object approaches the speed of light, its mass becomes infinite and it is unstable to go faster than any light travel.

Calculation:

Given,

The rest mass of the electron, m = 9.1 × 10^-31 kg

The speed of light, c = 3 × 10⁸ m/s

The mass-energy equivalence formula is given by,

E = mc²

E = 9.1 × 10^-31 kg × (3 × 10⁸ m/s)²

E = 81.9 × 10^-15 J [ 1J =1kgm²/s²]

Energy in electron volt (eV),

\(E=\frac{81.9\times 10^{-15}}{1.6\times 10^{-19}}\)

E = 0.511875 MeV

Hence, the mass-energy equivalence is 0.511875 MeV.