Its expectation value given by the Hamiltonian operator in quantum mechanics, it is the eigenvalue in H-hat psi equals E psi, a fact which makes it a conserved quantity.  
Its expectation value given by the Hamiltonian operator in quantum mechanics, it is the eigenvalue in H-hat psi equals E psi, a fact which makes it a conserved quantity.  Divided by h-bar, it gives the frequency of the time-dependent Schrodinger equation and the change in it, multiplied by delta t, must be greater than or equal to one half h-bar, according to the Heisenberg Uncertainty Principle.  For ten points, what is this scalar quantity equal to m c squared?
Its expectation value given by the Hamiltonian operator in quantum mechanics, it is the eigenvalue in H-hat psi equals E psi, a fact which makes it a conserved quantity.  
{Energy}