Quote:
Originally Posted by s0cratus
Question:
How does electron obey ‘ The law of conservation
and transformation energy/mass’ if according to Planck /
Einstein its energy is E=h*f and according to Dirac its
energy is +/ E=Mc^2 ?
==..

The real equation is:
E^2 = m^2 * c^4 + p^2 * c^2
The other relations you mention are valid in the limit of small mass and in the rest frame, respectively. Furthermore, the Dirac equation explicitly satisfies the full equation, not the approximate ones you've written.