Explain \[E=mc{}^{2}\] .

Hint: The formula for mass-energy equivalence is a principle put forward by Albert Einstein in his “Theory of Relativity”. The equivalence relationship and the theory of relativity brought about a new era in physics, especially concerning objects moving at the light-speed.

Complete step by step answer:
\[E=mc{}^{2}\] is known as the formula for energy-mass equivalence.
According to this formula, for mass to be converted into energy, then it should be traveling with a velocity equal to the velocity of light.
This equation was formulated by Einstein. In this formula, he tries to convey the following information about mass and energy:
Mass and energy are the same forms of a single object, and yet they are interchangeable or at least, that’s what we used to think.
When we are converting an object into energy, the resulting energy should be told in terms of speed of light. This is because the energy emitted will be in the form of electromagnetic radiation. When an object is moving with two-time more velocity than others, it possesses four times more energy than the other object. Thus, the speed of light is used as a conversion factor, to convert mass into pure energy. Thus, if we consider an object with a rest mass “m”, then the energy it is holding inside it is known with the above formula, \[E=mc{}^{2}\], where, e is the energy of the body when it is at rest and c is the speed of light.

Note: Though the energy and mass are different properties of the same thing, they are not physically convertible very easily. The energy of an object at rest is given by the above formula, but, to convert a mass into pure energy, the object should possess a velocity which is in exponential powers of the velocity of light.