Yes, the equation E = mc², also known as Einstein's mass-energy equivalence equation, is applicable at the nuclear level and can be applied to various particles such as protons, electrons, quarks, leptons, and bosons.
The equation states that the energy (E) of an object is equal to its mass (m) multiplied by the square of the speed of light (c). This equation shows that mass and energy are two forms of the same thing and can be converted into each other.
At the nuclear level, this equation becomes particularly relevant. In nuclear reactions, such as those occurring in the core of stars or in nuclear power plants, small amounts of mass are converted into energy according to E = mc². The conversion of mass into energy is the basis of nuclear power and nuclear weapons.
When it comes to particles such as protons, electrons, quarks, leptons, and bosons, the equation can also be applied. However, it's important to note that the equation alone does not provide a complete description of the behavior of these particles. The full understanding of their properties and interactions requires more comprehensive theories, such as quantum field theory and the Standard Model of particle physics. These theories incorporate Einstein's equation within their frameworks to describe the behavior of particles and their energy-mass relationships more accurately.